Question Number 54721 by 951172235v last updated on 09/Feb/19
$$\mathrm{Show}\:\mathrm{that} \\ $$$$\frac{\Sigma\left\{\mathrm{sin}\:\mathrm{2xtan}\:\left(\mathrm{y}−\mathrm{z}\right)\mathrm{cos}\:^{\mathrm{2}} \left(\mathrm{y}+\mathrm{z}\right)\right\}}{\Sigma\left\{\mathrm{cos}\:\mathrm{2xtan}\:\left(\mathrm{y}−\mathrm{z}\right)\mathrm{sin}\:^{\mathrm{2}} \left(\mathrm{y}+\mathrm{z}\right)\right\}\:\:\:}\:\:=\:\mathrm{tan}\:\mathrm{2xtan}\:\mathrm{2ytan}\:\mathrm{2z} \\ $$