I think I'm having a massive blonde moment...

How would I begin?

edit: also this question:

Here's my working so far:

$\displaystyle \frac{1+\frac{sin^2x}{cos^2x}}{cos^2x}$

$\displaystyle \frac{1+\frac{sin^2x}{1-sin^2x}}{1-sin^2x}$

I'm stuck here. I don't actually know what to do with multi-layered fractions, never been taught it.

I know the answer is

So clearly, I have to multiply by $\displaystyle 1-sin^2x$

How do I get there?

Also, this question:

part b,

Here's my working, I'm starting to think the question is wrong..?

$\displaystyle \frac{1}{cos\theta} + \frac{sin\theta}{cos\theta}=\frac{cos\theta}{1-sin\theta}$

$\displaystyle \frac{cos\theta+sin\theta cos\theta}{cos^2\theta}$

$\displaystyle \frac{cos\theta(1+sin\theta)}{1-sin^2\theta}$

What do I do from here?