$\dfrac {\sin ^{2}20-\cos ^{2}20} {1-\sin 40}=X$ ise tan20 nin x türünden eşiti nedir?

Question

Teşekkürler

Answer 1

$X=\frac{sin^2 20-cos^2 20}{1-sin40}=\frac{(sin20-cos20)(sin20+cos20)}{sin^2 20+cos^2 20-2.sin20.cos20}=\frac{(sin20-cos20)(sin20+cos20)}{(sin20-cos20)^2}=\frac{sin20+cos20}{sin20-cos20}$

$X.sin20-X.cos20=sin20+cos20$

$(X-1)sin20=(X+1)cos20$

$\frac{sin20}{cos20}=tan20=\frac{X+1}{X-1}$