in terms of tanx?
(sinx+icosx)^3
= (sinx)^3 + i3(sinx)^2cosx - 3sinx(cosx)^2 - i(cosx)^3
equating real and imaginary parts
sin3x= (sinx)^3 - 3sinx (cosx)^2
cos3x= 3(sinx)^2cosx - (cosx)^3
tan3x = [(sinx)^3 - 3sinx(cosx)^2]/[3(sinx)^2cosx - (cosx)^3]
divide by (cosx)^3
tan3x= [(tanx)^3 -...