A few questions I could use some help on:
1) express the function in terms of sine only.
g(x + h) - g(x)/h = -cosx (1-cosh/h) - sinx (sinh/h)
2) write the expression in terms of sine only
3 sin pi x + 3 (square root 3) cos pi x
3) prove the cofunction
csc(pi/2 - u) = sec u
Thanks in advance.