Exponential function and chain rule - find derivative

In summary, f'(x) = (e^{3x^2+x})(ln e)(6x+1) and f'(2) = 13e^14. It is important to note that using a calculator will only give an approximation of the exact value, which is 13e^14. Additionally, there is no need to write ln(e) as it is equal to 1.
  • #1
pbonnie
92
0

Homework Statement


If [itex] f(x) = e^{3x^2+x} [/itex], find f'(2)

Homework Equations


[itex]f'(x) = a^{g(x)}ln a g'(x)[/itex]

The Attempt at a Solution


[itex] f'(x) = (e^{3x^2+x})(ln e)(6x+1)[/itex]
[itex] f'(2) = (e^{3(2)^2+2})(ln e)(6(2)+1) [/itex]
[itex] = 2115812.288[/itex]

I was checking online and I'm seeing a different answer, but this is EXACTLY how my lesson is showing how to answer. Is this correct?
 
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  • #2
pbonnie said:

Homework Statement


If [itex] f(x) = e^{3x^2+x} [/itex], find f'(2)


Homework Equations


[itex]f'(x) = a^{g(x)}ln a g'(x)[/itex]


The Attempt at a Solution


[itex] f'(x) = (e^{3x^2+x})(ln e)(6x+1)[/itex]
[itex] f'(2) = (e^{3(2)^2+2})(ln e)(6(2)+1) [/itex]
[itex] = 2115812.288[/itex]

I was checking online and I'm seeing a different answer, but this is EXACTLY how my lesson is showing how to answer. Is this correct?

Looks to me like you are getting 13*e^(14). That's ok. But it's not equal to 2115812.288. How did you get that?
 
  • #3
Oh I'm not sure how I managed that. Thank you :)
 
  • #4
The exact value of f'(2) is 13e14. If you use a calculator on this, the result is only an approximation.

BTW, there's no point in writing ln(e), since it is 1 (exactly).
 

Related to Exponential function and chain rule - find derivative

What is an exponential function?

An exponential function is a mathematical function of the form f(x) = a^x, where a is a constant and x is the variable. It is often used to model growth or decay in various natural and physical phenomena.

How do you find the derivative of an exponential function?

To find the derivative of an exponential function, you can use the chain rule. The derivative of f(x) = a^x is given by f'(x) = a^x * ln(a).

What is the chain rule?

The chain rule is a rule in calculus that allows you to find the derivative of a composite function. It states that the derivative of a composite function f(g(x)) is equal to the derivative of the outer function f evaluated at the inner function g(x), multiplied by the derivative of the inner function g'(x).

How do you apply the chain rule to find the derivative of an exponential function?

To apply the chain rule to find the derivative of an exponential function, you first need to identify the outer function (in this case, f(x) = a^x) and the inner function (in this case, g(x) = x). Then, you can use the formula f'(x) = f(g(x)) * g'(x) to calculate the derivative.

Can you give an example of finding the derivative of an exponential function using the chain rule?

Yes, for example, let's find the derivative of f(x) = 2^x. We can identify the outer function f(x) = 2^x and the inner function g(x) = x. Then, using the chain rule, we have f'(x) = f(g(x)) * g'(x) = 2^x * ln(2). So, the derivative of f(x) = 2^x is f'(x) = 2^x * ln(2).

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