Question

Решите уравнения:
а) cos^2 x + sin^2 x = -sin^2 x
б) -cos^2 x = sin^2 x + cos x

Answer 1

$a) { cos}^{2} + {sin}^{2} = - {sin}^{2} \\ {cos}^{2} + {sin}^{2} = 1 \\ 1 = - {sin}^{2} \\ 1 + {sin}^{2} = 0 \\ {cos}^{2} = 0$
$- {cos}^{2} = {sin}^{2} + cos \\ cos = {sin}^{2} + {cos}^{2} \\ cos = 1 \\ 1 - cos = 0$