sin x = sin(π-x)=-sin(π+x)=-sin(-x)
cos x =-cos(π-x)=-cos(π+x)= cos(-x)
tan x =-tan(π-x)= tan(π+x)=-tan(-x)
sin x=cos (90 -x)
cos x=sin(90 -x)
sin(90 +x)=cos x
cos(90 +x)=-sin x
sin2x=2sinx cosx
cos2x= 1-2sin? x=- 1+2cos? x=cos? x-sin? x
tan2x=(2tanx)/( 1-tan? x)
Sin? x=( 1-cos2x)/2
Because? x=( 1+cos2x)/2
Tan? x =( 1-cos2x)/( 1+cos2x)
Can't play it all! What a waste of time! ! !