Question

вычислить 5sin^2(x)-1 при cosx = 1/2

Answer 1

$cowsx= frac{1}{2}\5sin^2x-1=5*(1-cos^2x)-1=5*(1-( frac{1}{2})^2)-1=\=5*(1- frac{1}{4})-1=5* frac{3}{4}-1= frac{15}{4}- frac{4}{4}= frac{11}{4}=2 frac{3}{4}=2,75$