Parts of sin are by thought, by the words that we say and be our deeds or actions.

sin(3A) = sin(2A + A) = sin(2A)*cos(A) + cos(2A)*sin(A)= sin(A+A)*cos(A) + cos(A+A)*sin(A)

= 2*sin(A)*cos(A)*cos(A) + {cos^2(A) - sin^2(A)}*sin(A)

= 2*sin(A)*cos^2(A) + sin(a)*cos^2(A) - sin^3(A)

= 3*sin(A)*cos^2(A) - sin^3(A)

(2 sin^2 x - 1)/(sin x - cos x) = sin x + cos x

(sin^2 x + sin^2 x - 1)/(sin x - cos x) =? sin x + cos x

[sin^2 x - (1 - sin^2 x)]/(sin x - cos x) =? sin x + cos x

(sin^2 x - cos^2 x)/(sin x - cos x) =? sin x + cos x

[(sin x - cos x)(sin x + cos x)]/(sin x - cos x) =? sin x + cos x

sin x + cos x = sin x + cos x

sin(2*pi) - not pie - is the same as sin(0) = 0