show that : `sin^2 alpha + sin^2(alpha +( 2pi)/n) +sin^2(alpha +( 4pi)/n) + .....` ` n ` terms ` = n/2`

show that :sin^(2)alpha+sin^(2)(alpha+(2 pi)/(n))+sin^(2)(alpha+(4 pi)/(n))+n terms =(n)/(2)

sin alpha+sin(alpha+((2pi)/3))+sin(alpha+((4pi)/3))=0

Show that 4sin alpha*sin(alpha+(pi)/(3))sin(alpha+2(pi)/(3))=sin3 alpha

prove that 4sin alpha*sin(alpha+(pi)/(3))*sin(alpha+(2 pi)/(3))=sin3 alpha

Sum the series: sin alpha - sin 2alpha + sin 3alpha - sin 4alpha + ... to n terms.

if cos^(2)alpha-sin alpha=(1)/(n) then alpha

Prove that: sin^(2)theta=sin^(2)alpha, then theta=n pi+-alpha,n in Z

The value of sin^(2)alpha+sin((pi)/(3)-alpha)sin((pi)/(3)+alpha) is

The expression (1 + sin 2 alpha )/( cos (2 alpha - 2pi) tan (alpha - (3pi)/(4 ))) -1/4 sin 2 alpha [ cot "" (alpha )/(2) + (alpha )/(2))] when simplified reduces to