Question

Упростить и вычислить cos^2 22°30' -sin^2 22° 30'

Answer 1

$cos^222^{circ}30^shortmid-sin^222^{circ}30^shortmid=cos(2cdot22^circ30^shortmid)=cos(45^circ)= dfrac{ sqrt{2} }{2}$