For angle>180 degree, use the formulae-
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