Question

Помогите решить
cos60°*(cos25°cos35°-sin25°sin35°)

Answer 1

cos60°*(cos25°cos35°-sin25°sin35°) = $cos60*cos(25+35)=cos(60)*cos(60)=cos(60)^2 = (\frac{1}{2})^2 = \frac{1}{4}$