Posted by **sh** on Friday, October 29, 2010 at 10:06pm.

Find the derivative of

f(x)=x(1-4^x)

f'(x)=(1-4^x)+ (-4^x)(ln-4)(-4)(x)

ln can't be negative. Is the derivative correct?

- Calculus -
**Reiny**, Friday, October 29, 2010 at 10:19pm
no, the second part of your product rule is not correct

lets just differentiate

1 - 4^x

that would be (-4^x)(ln4)

my final answer would be

f '(x) = (1-4^x) + x(-4^x)(ln4)

= 1 - 4^x - x(ln4)(4^x)

- Calculus -
**sh**, Friday, October 29, 2010 at 10:27pm
So the negative is not included,

for example f(x)=-2^x

f'(x) would be (-2^x)(ln2)?

Thanks!

- Calculus -
**Reiny**, Friday, October 29, 2010 at 10:30pm
I think you got it.

in your example you could look at -4^x

as -(4^x)

## Answer this Question

## Related Questions

- calc - derivative of (x^3/6)+(1/2x)? i got (x^2/2)-(1/2x^2) is that correct? and...
- Calculus--> bobpursley - How do you get m=0? from taking the second ...
- Calculus - derivatives - Okay, I want to find the derivative of (x^x)^(x^x)... ...
- Please check my Calculus - 1. Find all points of inflection of the function f(x...
- math - Find the derivative of y=3x-2(4^x) Here is my attempt: Derivative of 3x ...
- Calculus - 1.) Find the derivative of tan (sec x). 2.) Find the derivative if 1/...
- Calculus (Help) - Also I would like to know how to set this problem up in ...
- Calculus 1 - Find the derivative dy/dx for the following. Simplify your answer. ...
- Calculus - Any help would be much appreciated with the steps involved in each ...
- Calculus - Any help would be much appreciated with the steps involved in each ...

More Related Questions