Question

Помогите,пожалуйста

Answer 1

$ctg^2(x)(\frac{sin^2(x)}{cos^2(x)}) -cos^2(x)=\frac{cos^2(x)}{sin^2(x)}*\frac{sin^2(x)}{cos^2(x)}-cos^2(x)=1-\frac{1}{4}=\\=0,75$

Answer 2

$\tt ctg^2x(\dfrac{sin^2x}{cos^2x} )-cos^2x=\dfrac{cos^2x}{sin^2x}\cdot\dfrac{sin^2x}{cos^2x}-cos^2x=1-cos^2x=1-\dfrac{1}{4}=0,75$