i have 3 questions that i need help on for my test tommorw, so if you could answer any of them that would be great, thanks

prove each identity so L.S. = R.S.

1) sin x/2 = 1-cosx/2 (right side of equation is all under square root sign)

2)sin[cubed]x + cos[cubed]x = (1-sinxcosx)(sinx+cosx)

3) sin(squared)M [csc(squared)M + sec(squared)M] = sec(squared)M

any help is appreciated