Question

Упростите. (2cos^2(45*-a/2))/cosa

Answer 1

Используем формулу 2cos²t-1=cos2t
$\dfrac{2cos^2(45^o- \frac{\alpha}{2} )}{cos \alpha } = \dfrac{cos(90^o- \alpha )+1}{cos \alpha } = \dfrac{sin \alpha +1}{cos \alpha }$