Question

10  класс! тригонометрия!

Answer 1

$frac{2-4sin^2 a}{3+sin 2a} = frac{2-4sin^2 a}{3+2sin a cos a} = frac{2cos^2 a-2sin^2 a}{3cos^2a+2sin a cos a + 3sin^2 a} = \ = frac{2cot^2 a-2}{3cot^2a+2cot a + 3} = frac{2*4-2}{3*4-2*2 + 3} = frac{6}{11}$