$y(x)= x^2 - 6x + 22.09$ tangent [closed]

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$$y(x)= x^2-6x+22.09$$




I need to find the exact points where the tangents that pass through $0$, touch the curve using the first derivative. Any help would be great.










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closed as off-topic by Adrian Keister, amWhy, Leucippus, max_zorn, HK Lee Aug 31 at 1:40


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Adrian Keister, amWhy, Leucippus, max_zorn, HK Lee
If this question can be reworded to fit the rules in the help center, please edit the question.












  • Do you mean the points of tangency? The question reads like you want the intersections between the tangents, but that $(0,0)$ so I know it isn't what you mean. For the points where the tangent lines touch the parabola, correct?
    – saulspatz
    Aug 30 at 1:09










  • yeah (0,0) is already the point where tangents intersect Question is ambiguous
    – Deepesh Meena
    Aug 30 at 1:13










  • yep, i meant the points where the where the tangents touch the parabola
    – maths noob
    Aug 30 at 1:33














up vote
0
down vote

favorite













$$y(x)= x^2-6x+22.09$$




I need to find the exact points where the tangents that pass through $0$, touch the curve using the first derivative. Any help would be great.










share|cite|improve this question















closed as off-topic by Adrian Keister, amWhy, Leucippus, max_zorn, HK Lee Aug 31 at 1:40


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Adrian Keister, amWhy, Leucippus, max_zorn, HK Lee
If this question can be reworded to fit the rules in the help center, please edit the question.












  • Do you mean the points of tangency? The question reads like you want the intersections between the tangents, but that $(0,0)$ so I know it isn't what you mean. For the points where the tangent lines touch the parabola, correct?
    – saulspatz
    Aug 30 at 1:09










  • yeah (0,0) is already the point where tangents intersect Question is ambiguous
    – Deepesh Meena
    Aug 30 at 1:13










  • yep, i meant the points where the where the tangents touch the parabola
    – maths noob
    Aug 30 at 1:33












up vote
0
down vote

favorite









up vote
0
down vote

favorite












$$y(x)= x^2-6x+22.09$$




I need to find the exact points where the tangents that pass through $0$, touch the curve using the first derivative. Any help would be great.










share|cite|improve this question
















$$y(x)= x^2-6x+22.09$$




I need to find the exact points where the tangents that pass through $0$, touch the curve using the first derivative. Any help would be great.







calculus functions derivatives tangent-line






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edited Aug 30 at 2:18









Rafael Holanda

2,485522




2,485522










asked Aug 30 at 0:41









maths noob

63




63




closed as off-topic by Adrian Keister, amWhy, Leucippus, max_zorn, HK Lee Aug 31 at 1:40


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Adrian Keister, amWhy, Leucippus, max_zorn, HK Lee
If this question can be reworded to fit the rules in the help center, please edit the question.




closed as off-topic by Adrian Keister, amWhy, Leucippus, max_zorn, HK Lee Aug 31 at 1:40


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Adrian Keister, amWhy, Leucippus, max_zorn, HK Lee
If this question can be reworded to fit the rules in the help center, please edit the question.











  • Do you mean the points of tangency? The question reads like you want the intersections between the tangents, but that $(0,0)$ so I know it isn't what you mean. For the points where the tangent lines touch the parabola, correct?
    – saulspatz
    Aug 30 at 1:09










  • yeah (0,0) is already the point where tangents intersect Question is ambiguous
    – Deepesh Meena
    Aug 30 at 1:13










  • yep, i meant the points where the where the tangents touch the parabola
    – maths noob
    Aug 30 at 1:33
















  • Do you mean the points of tangency? The question reads like you want the intersections between the tangents, but that $(0,0)$ so I know it isn't what you mean. For the points where the tangent lines touch the parabola, correct?
    – saulspatz
    Aug 30 at 1:09










  • yeah (0,0) is already the point where tangents intersect Question is ambiguous
    – Deepesh Meena
    Aug 30 at 1:13










  • yep, i meant the points where the where the tangents touch the parabola
    – maths noob
    Aug 30 at 1:33















Do you mean the points of tangency? The question reads like you want the intersections between the tangents, but that $(0,0)$ so I know it isn't what you mean. For the points where the tangent lines touch the parabola, correct?
– saulspatz
Aug 30 at 1:09




Do you mean the points of tangency? The question reads like you want the intersections between the tangents, but that $(0,0)$ so I know it isn't what you mean. For the points where the tangent lines touch the parabola, correct?
– saulspatz
Aug 30 at 1:09












yeah (0,0) is already the point where tangents intersect Question is ambiguous
– Deepesh Meena
Aug 30 at 1:13




yeah (0,0) is already the point where tangents intersect Question is ambiguous
– Deepesh Meena
Aug 30 at 1:13












yep, i meant the points where the where the tangents touch the parabola
– maths noob
Aug 30 at 1:33




yep, i meant the points where the where the tangents touch the parabola
– maths noob
Aug 30 at 1:33










3 Answers
3






active

oldest

votes

















up vote
0
down vote



accepted










This is the parabola and the two tangent lines that pass through $(0,0)$:



enter image description here



In order to find the two tangent lines, let's consider the line equation in the slope-intercept form:
$$
y = ax + b
$$
Since both lines pass through $(0,0)$ we can easily deduct that $b=0$, so we have:
$$
y = ax
$$
In that equation, $a$ is the slope of the tangent line, which means it is its derivative:
$$
a = cfracdydx = 2x - 6
$$
So now we have a line equation that looks like this:
$$
y = ax = (2x - 6)x = 2x^2 - 6x
$$
Let's consider a point that passes through the parabola equation: $(x, x^2 - 6x + 22.09)$. Let's substitute this point in the tangent line equation:



$$
2x^2 - 6x = x^2 - 6x + 22.09 \
x^2 = 22.09 \
x = pm4.7
$$



Finally we have:



$y = 2x^2 - 6x rightarrow y = 2(4.7)^2 - 6(4.7) rightarrow y = 15.98$



$y = 2x^2 - 6x rightarrow y = 2(-4.7)^2 - 6(-4.7) rightarrow y = 72.38$



So the tangent lines intercept the parabola in the points $(4.7, 15.98)$ and $(-4.7, 72.38)$






share|cite|improve this answer





























    up vote
    0
    down vote













    Assuming I'm correct about what you are asking (see my comment), here is an outline of what you need to do. Pick some point $(x_0,y_0)$ on the curve an assume that the tangent to the curve at that point passes through $(0,0).$ Note that you are really only picking $x_0$ because once you've chosen $x_0$ that value of $y_0$ is determined. Now we knoe a point on the tangent line, namely $(x_0,y_0)$ and we know then slope, namely $y'(x_0).$



    That gives you the equation of the tangent line, so you just need to see what condition ob $x_0$ will force $(0,0)$ to lie on the line. That's easy; just assume $(0,0)$ satisfies the equation, and see what that tells you about $x_0$. Check to be sure that the steps are reversible.






    share|cite|improve this answer




















    • yes you are correct, I meant the points where the tangents touch the parabola
      – maths noob
      Aug 30 at 1:25

















    up vote
    0
    down vote













    Let the equation of the tangent line be $y=mx$



    The line and the parabola intersect where we have $$x^2-6x+22.09= mx$$double root.



    That is $$x^2-(m+6)x+22.09=0$$ has double roots.



    We need $$(m+6)^2-4(22.09)=0$$ which gives us$$ m=-6pm sqrt 22.09 =-6pm 4.7$$



    For each of these slopes you find the intersection of $y=mx$ and your parabola.






    share|cite|improve this answer






















    • this is $$ ??what?
      – Deepesh Meena
      Aug 30 at 1:21







    • 1




      I had to leave my mobile device , so I finished my solution later. Sorry for causing confusion. You can check the answer now.
      – Mohammad Riazi-Kermani
      Aug 30 at 1:29










    • Thanks Mohammad, very helpful
      – maths noob
      Aug 30 at 3:00

















    3 Answers
    3






    active

    oldest

    votes








    3 Answers
    3






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    0
    down vote



    accepted










    This is the parabola and the two tangent lines that pass through $(0,0)$:



    enter image description here



    In order to find the two tangent lines, let's consider the line equation in the slope-intercept form:
    $$
    y = ax + b
    $$
    Since both lines pass through $(0,0)$ we can easily deduct that $b=0$, so we have:
    $$
    y = ax
    $$
    In that equation, $a$ is the slope of the tangent line, which means it is its derivative:
    $$
    a = cfracdydx = 2x - 6
    $$
    So now we have a line equation that looks like this:
    $$
    y = ax = (2x - 6)x = 2x^2 - 6x
    $$
    Let's consider a point that passes through the parabola equation: $(x, x^2 - 6x + 22.09)$. Let's substitute this point in the tangent line equation:



    $$
    2x^2 - 6x = x^2 - 6x + 22.09 \
    x^2 = 22.09 \
    x = pm4.7
    $$



    Finally we have:



    $y = 2x^2 - 6x rightarrow y = 2(4.7)^2 - 6(4.7) rightarrow y = 15.98$



    $y = 2x^2 - 6x rightarrow y = 2(-4.7)^2 - 6(-4.7) rightarrow y = 72.38$



    So the tangent lines intercept the parabola in the points $(4.7, 15.98)$ and $(-4.7, 72.38)$






    share|cite|improve this answer


























      up vote
      0
      down vote



      accepted










      This is the parabola and the two tangent lines that pass through $(0,0)$:



      enter image description here



      In order to find the two tangent lines, let's consider the line equation in the slope-intercept form:
      $$
      y = ax + b
      $$
      Since both lines pass through $(0,0)$ we can easily deduct that $b=0$, so we have:
      $$
      y = ax
      $$
      In that equation, $a$ is the slope of the tangent line, which means it is its derivative:
      $$
      a = cfracdydx = 2x - 6
      $$
      So now we have a line equation that looks like this:
      $$
      y = ax = (2x - 6)x = 2x^2 - 6x
      $$
      Let's consider a point that passes through the parabola equation: $(x, x^2 - 6x + 22.09)$. Let's substitute this point in the tangent line equation:



      $$
      2x^2 - 6x = x^2 - 6x + 22.09 \
      x^2 = 22.09 \
      x = pm4.7
      $$



      Finally we have:



      $y = 2x^2 - 6x rightarrow y = 2(4.7)^2 - 6(4.7) rightarrow y = 15.98$



      $y = 2x^2 - 6x rightarrow y = 2(-4.7)^2 - 6(-4.7) rightarrow y = 72.38$



      So the tangent lines intercept the parabola in the points $(4.7, 15.98)$ and $(-4.7, 72.38)$






      share|cite|improve this answer
























        up vote
        0
        down vote



        accepted







        up vote
        0
        down vote



        accepted






        This is the parabola and the two tangent lines that pass through $(0,0)$:



        enter image description here



        In order to find the two tangent lines, let's consider the line equation in the slope-intercept form:
        $$
        y = ax + b
        $$
        Since both lines pass through $(0,0)$ we can easily deduct that $b=0$, so we have:
        $$
        y = ax
        $$
        In that equation, $a$ is the slope of the tangent line, which means it is its derivative:
        $$
        a = cfracdydx = 2x - 6
        $$
        So now we have a line equation that looks like this:
        $$
        y = ax = (2x - 6)x = 2x^2 - 6x
        $$
        Let's consider a point that passes through the parabola equation: $(x, x^2 - 6x + 22.09)$. Let's substitute this point in the tangent line equation:



        $$
        2x^2 - 6x = x^2 - 6x + 22.09 \
        x^2 = 22.09 \
        x = pm4.7
        $$



        Finally we have:



        $y = 2x^2 - 6x rightarrow y = 2(4.7)^2 - 6(4.7) rightarrow y = 15.98$



        $y = 2x^2 - 6x rightarrow y = 2(-4.7)^2 - 6(-4.7) rightarrow y = 72.38$



        So the tangent lines intercept the parabola in the points $(4.7, 15.98)$ and $(-4.7, 72.38)$






        share|cite|improve this answer














        This is the parabola and the two tangent lines that pass through $(0,0)$:



        enter image description here



        In order to find the two tangent lines, let's consider the line equation in the slope-intercept form:
        $$
        y = ax + b
        $$
        Since both lines pass through $(0,0)$ we can easily deduct that $b=0$, so we have:
        $$
        y = ax
        $$
        In that equation, $a$ is the slope of the tangent line, which means it is its derivative:
        $$
        a = cfracdydx = 2x - 6
        $$
        So now we have a line equation that looks like this:
        $$
        y = ax = (2x - 6)x = 2x^2 - 6x
        $$
        Let's consider a point that passes through the parabola equation: $(x, x^2 - 6x + 22.09)$. Let's substitute this point in the tangent line equation:



        $$
        2x^2 - 6x = x^2 - 6x + 22.09 \
        x^2 = 22.09 \
        x = pm4.7
        $$



        Finally we have:



        $y = 2x^2 - 6x rightarrow y = 2(4.7)^2 - 6(4.7) rightarrow y = 15.98$



        $y = 2x^2 - 6x rightarrow y = 2(-4.7)^2 - 6(-4.7) rightarrow y = 72.38$



        So the tangent lines intercept the parabola in the points $(4.7, 15.98)$ and $(-4.7, 72.38)$







        share|cite|improve this answer














        share|cite|improve this answer



        share|cite|improve this answer








        edited Aug 30 at 2:51

























        answered Aug 30 at 2:45









        HugoTeixeira

        256211




        256211




















            up vote
            0
            down vote













            Assuming I'm correct about what you are asking (see my comment), here is an outline of what you need to do. Pick some point $(x_0,y_0)$ on the curve an assume that the tangent to the curve at that point passes through $(0,0).$ Note that you are really only picking $x_0$ because once you've chosen $x_0$ that value of $y_0$ is determined. Now we knoe a point on the tangent line, namely $(x_0,y_0)$ and we know then slope, namely $y'(x_0).$



            That gives you the equation of the tangent line, so you just need to see what condition ob $x_0$ will force $(0,0)$ to lie on the line. That's easy; just assume $(0,0)$ satisfies the equation, and see what that tells you about $x_0$. Check to be sure that the steps are reversible.






            share|cite|improve this answer




















            • yes you are correct, I meant the points where the tangents touch the parabola
              – maths noob
              Aug 30 at 1:25














            up vote
            0
            down vote













            Assuming I'm correct about what you are asking (see my comment), here is an outline of what you need to do. Pick some point $(x_0,y_0)$ on the curve an assume that the tangent to the curve at that point passes through $(0,0).$ Note that you are really only picking $x_0$ because once you've chosen $x_0$ that value of $y_0$ is determined. Now we knoe a point on the tangent line, namely $(x_0,y_0)$ and we know then slope, namely $y'(x_0).$



            That gives you the equation of the tangent line, so you just need to see what condition ob $x_0$ will force $(0,0)$ to lie on the line. That's easy; just assume $(0,0)$ satisfies the equation, and see what that tells you about $x_0$. Check to be sure that the steps are reversible.






            share|cite|improve this answer




















            • yes you are correct, I meant the points where the tangents touch the parabola
              – maths noob
              Aug 30 at 1:25












            up vote
            0
            down vote










            up vote
            0
            down vote









            Assuming I'm correct about what you are asking (see my comment), here is an outline of what you need to do. Pick some point $(x_0,y_0)$ on the curve an assume that the tangent to the curve at that point passes through $(0,0).$ Note that you are really only picking $x_0$ because once you've chosen $x_0$ that value of $y_0$ is determined. Now we knoe a point on the tangent line, namely $(x_0,y_0)$ and we know then slope, namely $y'(x_0).$



            That gives you the equation of the tangent line, so you just need to see what condition ob $x_0$ will force $(0,0)$ to lie on the line. That's easy; just assume $(0,0)$ satisfies the equation, and see what that tells you about $x_0$. Check to be sure that the steps are reversible.






            share|cite|improve this answer












            Assuming I'm correct about what you are asking (see my comment), here is an outline of what you need to do. Pick some point $(x_0,y_0)$ on the curve an assume that the tangent to the curve at that point passes through $(0,0).$ Note that you are really only picking $x_0$ because once you've chosen $x_0$ that value of $y_0$ is determined. Now we knoe a point on the tangent line, namely $(x_0,y_0)$ and we know then slope, namely $y'(x_0).$



            That gives you the equation of the tangent line, so you just need to see what condition ob $x_0$ will force $(0,0)$ to lie on the line. That's easy; just assume $(0,0)$ satisfies the equation, and see what that tells you about $x_0$. Check to be sure that the steps are reversible.







            share|cite|improve this answer












            share|cite|improve this answer



            share|cite|improve this answer










            answered Aug 30 at 1:17









            saulspatz

            11.4k21324




            11.4k21324











            • yes you are correct, I meant the points where the tangents touch the parabola
              – maths noob
              Aug 30 at 1:25
















            • yes you are correct, I meant the points where the tangents touch the parabola
              – maths noob
              Aug 30 at 1:25















            yes you are correct, I meant the points where the tangents touch the parabola
            – maths noob
            Aug 30 at 1:25




            yes you are correct, I meant the points where the tangents touch the parabola
            – maths noob
            Aug 30 at 1:25










            up vote
            0
            down vote













            Let the equation of the tangent line be $y=mx$



            The line and the parabola intersect where we have $$x^2-6x+22.09= mx$$double root.



            That is $$x^2-(m+6)x+22.09=0$$ has double roots.



            We need $$(m+6)^2-4(22.09)=0$$ which gives us$$ m=-6pm sqrt 22.09 =-6pm 4.7$$



            For each of these slopes you find the intersection of $y=mx$ and your parabola.






            share|cite|improve this answer






















            • this is $$ ??what?
              – Deepesh Meena
              Aug 30 at 1:21







            • 1




              I had to leave my mobile device , so I finished my solution later. Sorry for causing confusion. You can check the answer now.
              – Mohammad Riazi-Kermani
              Aug 30 at 1:29










            • Thanks Mohammad, very helpful
              – maths noob
              Aug 30 at 3:00














            up vote
            0
            down vote













            Let the equation of the tangent line be $y=mx$



            The line and the parabola intersect where we have $$x^2-6x+22.09= mx$$double root.



            That is $$x^2-(m+6)x+22.09=0$$ has double roots.



            We need $$(m+6)^2-4(22.09)=0$$ which gives us$$ m=-6pm sqrt 22.09 =-6pm 4.7$$



            For each of these slopes you find the intersection of $y=mx$ and your parabola.






            share|cite|improve this answer






















            • this is $$ ??what?
              – Deepesh Meena
              Aug 30 at 1:21







            • 1




              I had to leave my mobile device , so I finished my solution later. Sorry for causing confusion. You can check the answer now.
              – Mohammad Riazi-Kermani
              Aug 30 at 1:29










            • Thanks Mohammad, very helpful
              – maths noob
              Aug 30 at 3:00












            up vote
            0
            down vote










            up vote
            0
            down vote









            Let the equation of the tangent line be $y=mx$



            The line and the parabola intersect where we have $$x^2-6x+22.09= mx$$double root.



            That is $$x^2-(m+6)x+22.09=0$$ has double roots.



            We need $$(m+6)^2-4(22.09)=0$$ which gives us$$ m=-6pm sqrt 22.09 =-6pm 4.7$$



            For each of these slopes you find the intersection of $y=mx$ and your parabola.






            share|cite|improve this answer














            Let the equation of the tangent line be $y=mx$



            The line and the parabola intersect where we have $$x^2-6x+22.09= mx$$double root.



            That is $$x^2-(m+6)x+22.09=0$$ has double roots.



            We need $$(m+6)^2-4(22.09)=0$$ which gives us$$ m=-6pm sqrt 22.09 =-6pm 4.7$$



            For each of these slopes you find the intersection of $y=mx$ and your parabola.







            share|cite|improve this answer














            share|cite|improve this answer



            share|cite|improve this answer








            edited Aug 30 at 1:27

























            answered Aug 30 at 1:20









            Mohammad Riazi-Kermani

            31k41853




            31k41853











            • this is $$ ??what?
              – Deepesh Meena
              Aug 30 at 1:21







            • 1




              I had to leave my mobile device , so I finished my solution later. Sorry for causing confusion. You can check the answer now.
              – Mohammad Riazi-Kermani
              Aug 30 at 1:29










            • Thanks Mohammad, very helpful
              – maths noob
              Aug 30 at 3:00
















            • this is $$ ??what?
              – Deepesh Meena
              Aug 30 at 1:21







            • 1




              I had to leave my mobile device , so I finished my solution later. Sorry for causing confusion. You can check the answer now.
              – Mohammad Riazi-Kermani
              Aug 30 at 1:29










            • Thanks Mohammad, very helpful
              – maths noob
              Aug 30 at 3:00















            this is $$ ??what?
            – Deepesh Meena
            Aug 30 at 1:21





            this is $$ ??what?
            – Deepesh Meena
            Aug 30 at 1:21





            1




            1




            I had to leave my mobile device , so I finished my solution later. Sorry for causing confusion. You can check the answer now.
            – Mohammad Riazi-Kermani
            Aug 30 at 1:29




            I had to leave my mobile device , so I finished my solution later. Sorry for causing confusion. You can check the answer now.
            – Mohammad Riazi-Kermani
            Aug 30 at 1:29












            Thanks Mohammad, very helpful
            – maths noob
            Aug 30 at 3:00




            Thanks Mohammad, very helpful
            – maths noob
            Aug 30 at 3:00


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