Question

Simplify and write the trig expression in terms of sin and cos

Answer 1

We have:

$cot(-x)cos(-x)+sin(-x)=-\frac{1}{f(x)}$

Then we use trigonometric identities to change the negative sign of the trigonometric functions, so:

$-sin(x)-cot(x)cos(x)=-\frac{1}{f(x)}$

We clear f(x):

$f(x)=\frac{1}{sin(x)+cot(x)cos(x)}=\frac{1}{sin(x)+\frac{cos(x)}{sin(x)}cos(x)}=\frac{1}{sin(x)+\frac{cos^2(x)}{sin(x)}}$

we simply what we can:

$f(x)=\frac{1}{\frac{sin^2(x)+cos^2(x)}{sin(x)}}=sin(x)$

Thus, the correct answer is;

$f(x)=sin(x)$