Question: "Find the derivative of arccos(arcsin(t))".

which should be same as cos^-1 (sin^-1 (t))

I have no idea how to approach this problem. I know that sin(arcsinx) = x if [-1,1] and arc(sinx) = x if [-pi/2, pi/2] but my prof never explained the arccos and thats why I really don't know how to start doing this question!