Simplifying the Derivative of y=cos[(8t-7)^{\frac{-6}{7}}]

[temaire]

Homework Statement

Find the first derivative of the function $$y=cos[(8t-7)^{\frac{-6}{7}}]$$

The Attempt at a Solution

Here is my answer:
$$\frac{dy}{dx}=\frac{48sin[(8t-7)^{\frac{-6}{7}}]}{7(8t-7)^{\frac{13}{7}}}$$

How can I simplify this further?

 

[Dick]

You can't simplify it in any significant way. Just leave it as it is.

 

[temaire]

You can't simplify it in any significant way. Just leave it as it is.

Well the thing is, I'm using a program called MathXL, and when I try to submit this answer, it rejects it.

 

[temaire]

So you think the program is just malfunctioning? I doubt this because a friend of mine had the same problem as well.

 

[Dick]

I know your answer is correct, even if the machine doesn't.

 

[temaire]

The answer is correct, but it looks like they wanted all the exponents to be positive. I put this in, and got it right.

$$\frac{dy}{dx}=\frac{48sin[\frac{1}{(8t-7)^{\frac{6}{7}}}]}{7(8t-7)^{\frac{13}{7}}}$$

 

[Dick]

Good job. Shows you the limitations of the program. I really wish good answers weren't subjected to this hoop jumping.