" 5."cos^(2)(45^(0)-alpha)+cos^(2)(15^(0)+alpha)-cos^(2)(15^(0)-alpha)=

cos^(2)(45^(@)-alpha)+cos^(2)(15^(@)+alpha)-cos^(2)(15^(0)-alpha)=

cos^(2) ( 45^(@) - alpha ) + cos^(2) (15^(@) + alpha ) - cos^(2)(15^(@)-alpha)=

cos alpha+cos(120^(@)+alpha)+cos(120^(@)-alpha)=0

If |(sin^(2)alpha,cos^(2)alpha),(cos^(2)alpha,sin^(2)alpha)|=0,alphain(0,pi) , then the values of alpha are

Prove that, cos alpha + cos(120^(@) + alpha) + cos (120^(@) - alpha) = 0

If 2sec^(2)alpha-sec^(4)alpha-2cos ec^(2)alpha+cos ec^(4)alpha=(15)/(4) then tan alpha=

If A=cos^(2)alpha+cos^(2)(alpha+beta)-2cos alpha cos beta cos(alpha+beta) then (i) A>1 (ii) 0<=A<=1 (iii) -1<=A<0 (iv) A<-1

If cos5 alpha=cos^(5)alpha, where alpha in(0,(pi)/(2)) then find the possible values of (sec^(2)alpha+cos ec^(2)alpha+cot^(2)alpha)

(1)/(cos alpha+cos3 alpha)+(1)/(cos alpha+cos5 alpha)...(.1)/(cos alpha+cos(2n+1)alpha)