I have a homework assignment due tonight, and I feel like this guy ---->

Here are the two questions I still do not understand

1.) Write in slope intercept form the equation for the tangent line for the curve y=sin(x) at x=(pi/3).

What I do know is the f'(x)=cos(x).

Next, do I plug pi/3 into the derivative?? I'm lost at this point.

2.) Use the definition of the derivative to compute the derivative of f(x) = squareroot(x-3)

so.. f(x)=(x-3)^(1/2)

could I do f(x)=(1/2)(x-3)^(-1/2) ?

and where would I go after that?