Question

3(cos^2 31- sin^2 31) / 10sin^2 31 - 5

Answer 1

$frac{3(cos^231-sin^231)}{10sin^231-5}= frac{3cos62}{5(2sin^231-1)}= frac{3cos62}{-5(1-2sin^231)}= frac{3cos62}{-5cos62}=- frac35=-0,6.$