I'm having a complete mind blank..and can't do these two questions...
any help would be greatly appreciated.
1) By writing sin3x as sin (2x+x) show that sin 3x = 3sinx - 4sin(cubed)x
i know that sin(2x+x) = sin2xcosx + cos2xsinx but i don't know where to go from there.
2) f(x) = 1- 3 + 3 x does not = -2
show that f(x) = x(squared) + x + 1 x does not = -2
please help if you can do either of these.