`4(cos^3 2 0^(@)+cos^3 4 0^(@))=3(cos2 0^(@)+cos4 0^(@))`

Prove that cos 2 0^(@)cos4 0^(@)cos6 0^(@)cos8 0^(@)=1/16

cos4 0^(@)+cos2 0^(@))=3(cos1 0^(@)+sin2 0^(@)) 40 CUSOUcos 40^@ + cos 20O 4(cos310^@ + sin320^@) = 3(cos 10^@ + sin20^@)N3.1 = 4

Evaluate (2cos4 0^(@)-cos2 0^(@))/(sin2 0^(@)

The value of cos^(2)10^(0)-cos10^(0)cos50^(@)+cos^(2)50^(@) is equal to (4)/(3)(b)(1)/(3)(c)(3)/(4)(d)3

cos5^(0)+cos24^(0)+cos175^(0)+cos204^(0)+cos300^(@)= 1) (1)/(2) 2) 13)(3)/(2)4)2

The value of 3sin30^(0)-4sin^(3)30^(@)+4cos^(3)30^(0)-3cos30^(@)

Prove that 2 (sin ^ (6) A + cos ^ (6) A) -3 (sin ^ (4) A + cos ^ (4) A) + 1 = 0

Prove that cos^(3)A+cos^(3)(120^(@)+A)+cos^(3)(240^(0)+A)=(3)/(4)cos3A

cos1^(0)+cos2^(0)+cos3^(0)+ . . .+cos180^(0) =