This problem demonstrates how you enter function answers into WebWork.

First enter the function $\sin\; x$. When entering the function, you should enter sin(x), but WebWork will also accept sin x or even sinx. If you remember your trig identities, sin(x) = -cos(x+pi/2) and WebWork will accept this or any other function equal to sin(x), for example, sin(x) + sin(x)**2 + cos(x)**2 - 1 (or sin(x) + sin^2(x) + cos^2(x) - 1)

We said you should enter sin(x) even though WebWork will also accept sin x or even sinx because you are less likely to make a mistake. Try entering sin(2x) without the parentheses and you may be surprised at what you get. Use the Preview button to see what you get. WebWork will evaluate functions (such as sin) before doing anything else, so sin 2x means first apply sine, which gives sin(2), and then mutiply by x. Try it.

Now enter the function $2\cos t$. Note this is a function of $t$ and not $x$. Try entering 2cos x and see what happens.