вычислить: (cos20+sin50-cos80) / ((1+cos280)^0.5)

Question

вычислить: (cos20+sin50-cos80) / ((1+cos280)^0.5)

Answer 1

(cos20+sin50-cos80)/√(1+cos^2(80))=

=((cos20-cos80)+sin50)/√(1+cos^2(80))=

=(-2sin50*sin30)+sin50)/√(1+cos^2(80))=

=(-sin50+sin50)/√(1+cos^2(80))=0/√(1+cos^2(80))=0