Question Number 76012 by mathocean1 last updated on 22/Dec/19
$$\mathrm{show}\:\mathrm{that}\: \\ $$$$\mathrm{1}−\mathrm{3sin}^{\mathrm{2}} {x}\mathrm{cos}^{\mathrm{2}} {x}=\frac{\mathrm{5}}{\mathrm{8}}+\frac{\mathrm{3}}{\mathrm{8}}\boldsymbol{\mathrm{cos}}\mathrm{4}\boldsymbol{{x}} \\ $$
Answered by benjo last updated on 22/Dec/19
$$\mathrm{1}−\mathrm{3}/\mathrm{4}\left({sin}^{\mathrm{2}} \mathrm{2}{x}\right)= \\ $$$$\mathrm{1}−\mathrm{3}/\mathrm{4}\left(\:\mathrm{1}−{cos}\mathrm{4}{x}\right)/\mathrm{2} \\ $$$$\mathrm{5}/\mathrm{8}+\mathrm{3}/\mathrm{8}{cos}\mathrm{4}{x} \\ $$
Commented by mathocean1 last updated on 22/Dec/19
$$\mathrm{please}\:\mathrm{how}\:\mathrm{have}\:\mathrm{you}\:\mathrm{done}\:\mathrm{to}\:\mathrm{have} \\ $$$$\mathrm{the}\:\mathrm{first}\:\mathrm{line}? \\ $$
Commented by benjo last updated on 22/Dec/19
