For each of the following functions, determine the maximum and minimum values of y and the.....?

Question

least positive values of x at which these occur.

a) y = 5-4sin(x+30°)

b) y = 8-3cos²x

c) y = 60 / [(1+sin²)(2x-15°)

AHHHHHHHH
I have a love hate relationship with maths.

Answer 1

min at pi/3 and max at4pi/3

min at 0, max at pi/2, min at pi if you do not regard 0 as positive

min at Pi/2, max at 11pi/12