Question

Найди значение выражения: 4cos^2 731°+4sin^2 349°

Answer 1

$4cos^2731^\circ +4sin^2349^\circ =\\\\=4\cdot (cos^2(360^\circ \cdot 2+11^\circ )+sin^2(360^\circ -11^\circ))=\\\\=4\cdot (cos^211^\circ+(-sin11^\circ)^2)=\\\\=4\cdot (cos^211^\circ +sin^211^\circ )=4\cdot 1=4\\\\\\P.S.\; \; \; sin(360^\circ -11^\circ)=sin(-11^\circ )=-sin11^\circ \\\\sin^2(360^\circ -11^\circ )=(-sin11^\circ )^2=+\, sin^211^\circ$