Differentiate $e^7x^3-frac53$
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up vote
3
down vote
favorite
For this equation I'm using the following property
$$f(x)=e^kx$$
$$f'(x)=ke^kx$$
As well as the product rule
$$f(x)=uv$$
$$f'(x)=u'v+uv'$$
I factorize $x$ on $e$'s exponent and then use the first property to differentiate:
$$e^7x^3-frac53=e^x(7x^2)-frac53=7x^2*e^7x^3-frac53$$
Is his fully differentiated? Or do I have to apply the product rule to $7x^2$? Any other steps I'm missing?
derivatives
add a comment |Â
up vote
3
down vote
favorite
For this equation I'm using the following property
$$f(x)=e^kx$$
$$f'(x)=ke^kx$$
As well as the product rule
$$f(x)=uv$$
$$f'(x)=u'v+uv'$$
I factorize $x$ on $e$'s exponent and then use the first property to differentiate:
$$e^7x^3-frac53=e^x(7x^2)-frac53=7x^2*e^7x^3-frac53$$
Is his fully differentiated? Or do I have to apply the product rule to $7x^2$? Any other steps I'm missing?
derivatives
$7x^2$ isn't a constant.
â poyea
Aug 24 at 10:42
1
Ahem. $uv$ is a product, not a quotient.
â Sean Roberson
Aug 24 at 10:42
@SeanRoberson lmao my bad
â Pablo
Aug 24 at 10:43
add a comment |Â
up vote
3
down vote
favorite
up vote
3
down vote
favorite
For this equation I'm using the following property
$$f(x)=e^kx$$
$$f'(x)=ke^kx$$
As well as the product rule
$$f(x)=uv$$
$$f'(x)=u'v+uv'$$
I factorize $x$ on $e$'s exponent and then use the first property to differentiate:
$$e^7x^3-frac53=e^x(7x^2)-frac53=7x^2*e^7x^3-frac53$$
Is his fully differentiated? Or do I have to apply the product rule to $7x^2$? Any other steps I'm missing?
derivatives
For this equation I'm using the following property
$$f(x)=e^kx$$
$$f'(x)=ke^kx$$
As well as the product rule
$$f(x)=uv$$
$$f'(x)=u'v+uv'$$
I factorize $x$ on $e$'s exponent and then use the first property to differentiate:
$$e^7x^3-frac53=e^x(7x^2)-frac53=7x^2*e^7x^3-frac53$$
Is his fully differentiated? Or do I have to apply the product rule to $7x^2$? Any other steps I'm missing?
derivatives
edited Aug 24 at 10:43
asked Aug 24 at 10:38
Pablo
33312
33312
$7x^2$ isn't a constant.
â poyea
Aug 24 at 10:42
1
Ahem. $uv$ is a product, not a quotient.
â Sean Roberson
Aug 24 at 10:42
@SeanRoberson lmao my bad
â Pablo
Aug 24 at 10:43
add a comment |Â
$7x^2$ isn't a constant.
â poyea
Aug 24 at 10:42
1
Ahem. $uv$ is a product, not a quotient.
â Sean Roberson
Aug 24 at 10:42
@SeanRoberson lmao my bad
â Pablo
Aug 24 at 10:43
$7x^2$ isn't a constant.
â poyea
Aug 24 at 10:42
$7x^2$ isn't a constant.
â poyea
Aug 24 at 10:42
1
1
Ahem. $uv$ is a product, not a quotient.
â Sean Roberson
Aug 24 at 10:42
Ahem. $uv$ is a product, not a quotient.
â Sean Roberson
Aug 24 at 10:42
@SeanRoberson lmao my bad
â Pablo
Aug 24 at 10:43
@SeanRoberson lmao my bad
â Pablo
Aug 24 at 10:43
add a comment |Â
3 Answers
3
active
oldest
votes
up vote
2
down vote
accepted
We need to use chain rule
$$(e^f(x))'=f'(x)e^f(x)$$
with
$$f(x)=7x^3-frac53 implies f'(x)=21x^2$$
add a comment |Â
up vote
3
down vote
Remember that when differentiating exponential functions you always get a copy back, multiplied by some other stuff. So we know the derivative contains the term $expleft( 7x^3 - frac53 right)$.
Now we use the chain. The derivative of the power is $21x^2$ by the usual rules. Here, $frac53$ is a constant and so its derivative vanishes everywhere.
Thus, the derivative is $21x^2 cdot expleft( 7x^3 - frac53 right)$.
(Here $exp(x)$ means $e^x$.)
add a comment |Â
up vote
2
down vote
This is not quite right. It's true that
$$
fracmathrmdmathrmdxleft[ e^kx right] = ke^kx,,
$$
but this is because
$$
fracmathrmdmathrmdxleft[ e^f(x) right] = f'(x)cdot e^f(x),.
$$
Hence for your question you have
$$
fracmathrmdmathrmdxleft[ e^7x^3 - frac53 right] =
fracmathrmdmathrmdxleft[ 7x^3 - frac53 right]e^7x^3 - frac53,.
$$
Can you finish it from here?
got it. i gotta differentiate $7x^3$
â Pablo
Aug 24 at 10:45
You need to differentiate $7x^3 - frac53$, yes.
â Bill Wallis
Aug 24 at 10:48
add a comment |Â
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
2
down vote
accepted
We need to use chain rule
$$(e^f(x))'=f'(x)e^f(x)$$
with
$$f(x)=7x^3-frac53 implies f'(x)=21x^2$$
add a comment |Â
up vote
2
down vote
accepted
We need to use chain rule
$$(e^f(x))'=f'(x)e^f(x)$$
with
$$f(x)=7x^3-frac53 implies f'(x)=21x^2$$
add a comment |Â
up vote
2
down vote
accepted
up vote
2
down vote
accepted
We need to use chain rule
$$(e^f(x))'=f'(x)e^f(x)$$
with
$$f(x)=7x^3-frac53 implies f'(x)=21x^2$$
We need to use chain rule
$$(e^f(x))'=f'(x)e^f(x)$$
with
$$f(x)=7x^3-frac53 implies f'(x)=21x^2$$
answered Aug 24 at 10:42
gimusi
69.7k73686
69.7k73686
add a comment |Â
add a comment |Â
up vote
3
down vote
Remember that when differentiating exponential functions you always get a copy back, multiplied by some other stuff. So we know the derivative contains the term $expleft( 7x^3 - frac53 right)$.
Now we use the chain. The derivative of the power is $21x^2$ by the usual rules. Here, $frac53$ is a constant and so its derivative vanishes everywhere.
Thus, the derivative is $21x^2 cdot expleft( 7x^3 - frac53 right)$.
(Here $exp(x)$ means $e^x$.)
add a comment |Â
up vote
3
down vote
Remember that when differentiating exponential functions you always get a copy back, multiplied by some other stuff. So we know the derivative contains the term $expleft( 7x^3 - frac53 right)$.
Now we use the chain. The derivative of the power is $21x^2$ by the usual rules. Here, $frac53$ is a constant and so its derivative vanishes everywhere.
Thus, the derivative is $21x^2 cdot expleft( 7x^3 - frac53 right)$.
(Here $exp(x)$ means $e^x$.)
add a comment |Â
up vote
3
down vote
up vote
3
down vote
Remember that when differentiating exponential functions you always get a copy back, multiplied by some other stuff. So we know the derivative contains the term $expleft( 7x^3 - frac53 right)$.
Now we use the chain. The derivative of the power is $21x^2$ by the usual rules. Here, $frac53$ is a constant and so its derivative vanishes everywhere.
Thus, the derivative is $21x^2 cdot expleft( 7x^3 - frac53 right)$.
(Here $exp(x)$ means $e^x$.)
Remember that when differentiating exponential functions you always get a copy back, multiplied by some other stuff. So we know the derivative contains the term $expleft( 7x^3 - frac53 right)$.
Now we use the chain. The derivative of the power is $21x^2$ by the usual rules. Here, $frac53$ is a constant and so its derivative vanishes everywhere.
Thus, the derivative is $21x^2 cdot expleft( 7x^3 - frac53 right)$.
(Here $exp(x)$ means $e^x$.)
answered Aug 24 at 10:46
Sean Roberson
5,95231226
5,95231226
add a comment |Â
add a comment |Â
up vote
2
down vote
This is not quite right. It's true that
$$
fracmathrmdmathrmdxleft[ e^kx right] = ke^kx,,
$$
but this is because
$$
fracmathrmdmathrmdxleft[ e^f(x) right] = f'(x)cdot e^f(x),.
$$
Hence for your question you have
$$
fracmathrmdmathrmdxleft[ e^7x^3 - frac53 right] =
fracmathrmdmathrmdxleft[ 7x^3 - frac53 right]e^7x^3 - frac53,.
$$
Can you finish it from here?
got it. i gotta differentiate $7x^3$
â Pablo
Aug 24 at 10:45
You need to differentiate $7x^3 - frac53$, yes.
â Bill Wallis
Aug 24 at 10:48
add a comment |Â
up vote
2
down vote
This is not quite right. It's true that
$$
fracmathrmdmathrmdxleft[ e^kx right] = ke^kx,,
$$
but this is because
$$
fracmathrmdmathrmdxleft[ e^f(x) right] = f'(x)cdot e^f(x),.
$$
Hence for your question you have
$$
fracmathrmdmathrmdxleft[ e^7x^3 - frac53 right] =
fracmathrmdmathrmdxleft[ 7x^3 - frac53 right]e^7x^3 - frac53,.
$$
Can you finish it from here?
got it. i gotta differentiate $7x^3$
â Pablo
Aug 24 at 10:45
You need to differentiate $7x^3 - frac53$, yes.
â Bill Wallis
Aug 24 at 10:48
add a comment |Â
up vote
2
down vote
up vote
2
down vote
This is not quite right. It's true that
$$
fracmathrmdmathrmdxleft[ e^kx right] = ke^kx,,
$$
but this is because
$$
fracmathrmdmathrmdxleft[ e^f(x) right] = f'(x)cdot e^f(x),.
$$
Hence for your question you have
$$
fracmathrmdmathrmdxleft[ e^7x^3 - frac53 right] =
fracmathrmdmathrmdxleft[ 7x^3 - frac53 right]e^7x^3 - frac53,.
$$
Can you finish it from here?
This is not quite right. It's true that
$$
fracmathrmdmathrmdxleft[ e^kx right] = ke^kx,,
$$
but this is because
$$
fracmathrmdmathrmdxleft[ e^f(x) right] = f'(x)cdot e^f(x),.
$$
Hence for your question you have
$$
fracmathrmdmathrmdxleft[ e^7x^3 - frac53 right] =
fracmathrmdmathrmdxleft[ 7x^3 - frac53 right]e^7x^3 - frac53,.
$$
Can you finish it from here?
answered Aug 24 at 10:43
Bill Wallis
2,2261826
2,2261826
got it. i gotta differentiate $7x^3$
â Pablo
Aug 24 at 10:45
You need to differentiate $7x^3 - frac53$, yes.
â Bill Wallis
Aug 24 at 10:48
add a comment |Â
got it. i gotta differentiate $7x^3$
â Pablo
Aug 24 at 10:45
You need to differentiate $7x^3 - frac53$, yes.
â Bill Wallis
Aug 24 at 10:48
got it. i gotta differentiate $7x^3$
â Pablo
Aug 24 at 10:45
got it. i gotta differentiate $7x^3$
â Pablo
Aug 24 at 10:45
You need to differentiate $7x^3 - frac53$, yes.
â Bill Wallis
Aug 24 at 10:48
You need to differentiate $7x^3 - frac53$, yes.
â Bill Wallis
Aug 24 at 10:48
add a comment |Â
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$7x^2$ isn't a constant.
â poyea
Aug 24 at 10:42
1
Ahem. $uv$ is a product, not a quotient.
â Sean Roberson
Aug 24 at 10:42
@SeanRoberson lmao my bad
â Pablo
Aug 24 at 10:43