1. ## Differentiation

Hi, i'm stuck as to what to do with this problem.

Find the gradient of y with respect to x

$y=\frac{3\sqrt{\theta^2+1}}{1/2cos(x^2+2\theta)}$

I started by doing this:

$y=\frac{6\sqrt{\theta^2+1}}{cos(x^2+2\theta)}$

But i don't know how to resolve $cos(x^2+2\theta)$

Is theta a constant that i just treat as any normal number?

This would leave the top part as 0 once differentiated. Is this right?

I can't find anything in my textbooks referring to two unknowns.

Any help is appreciated.

2. Originally Posted by andyw
Hi, i'm stuck as to what to do with this problem.

Find the gradient of y with respect to x

$y=\frac{3\sqrt{\theta^2+1}}{1/2cos(x^2+2\theta)}$

I started by doing this:

$y=\frac{6\sqrt{\theta^2+1}}{cos(x^2+2\theta)}$

But i don't know how to resolve $cos(x^2+2\theta)$

Is theta a constant that i just treat as any normal number?

This would leave the top part as 0 once differentiated. Is this right?

I can't find anything in my textbooks referring to two unknowns.

Any help is appreciated.
Either $\theta$ is a constant or you are asked to find a "partial derivative" with respect to x which means treating $\theta$ like a constant- so either way, the derivative of the numerator is just 0.