sin(180+A ) = - sinA

cos (180+A) = - cosA

tan(180+A )= tanA

cos of any angle lags behind sin graph by 90 degree

Exa- cos 90 has same value as sin (90+90)=sin 180

cos of an angle lags behind the sine by phase difference of 90 degree.

i.e sin 90= cos(90-90)=cos 0