Question

2sin^2a+6cos^2a если sin a=-0.2

Answer 1

$2sin^2 a+6cos^2 a=2sin^2 a+6(1-sin^2 a)=2sin^2 a+6-6sin^2 a=$
$6-4sin^2 a=6-4*(sin a)^2=6-4*(-0.2)^2=5.84$
ответ: 5.84