The trick is to start with sin(3x) and simplify and it will come out with an equation that you can solve for sin³(x). sin(3x) = sin(2x+x) = sin(2x)cos(x)+cos(2x)sin(x) = 2sin(x)cos(x)cos(x)+cos(2x)sin(x) = 2sin(x)cos²(x)+[1-2sin²(x)]sin(x) = 2sin(x)[1-sin²(x)]+[1-2sin²(x)]sin(x) = 2sin(x) - 2sin³(x) + sin(x) - 2sin³(x) = 3sin(x) - 4sin³(x) So sin(3x) = 3sin(x) - 4sin³(x) 4sin³(x) = 3sin(x) - sin(3x) sin³(x) =sin(x) - sin(3x) Edwin