Question

(sina+sinb)^2+(cosa+cosb)^2 - помогите упростить тригонометрия)

Answer 1

sin^2a+2*sina*sinb+sin^2b+cos^2a+2*cosa*cosb+cos^2=1+1+2(cos (a-b) )=2(1+cos(a-b)).

Answer 2

(sina+sinb)^2+(cosa+cosb)^2=sina^2+2sina*sinb+sinb^2+cosa^2+2cosa*cosb+cosb^2=

=1+1+2sina*sinb+2cosa*cosb=2+2cos(a-b)=2(1+cos(a-b))