`4cos3 6^(@)+cos(7 1/2)^0=`

4cos36 ^ (@) + cos (7 (1) / (2)) ^ (0) =

If sin A + sin^(2)A + sin^(3)A =1 , then , prove that cos^(6) A - 4 cos^(4) A + 8 cos^(2) A =4 .

6cos^(3)x+cos^(2)x-1=0

A value of theta in (0, pi//3), for which |{:(1+"cos"^(2)theta, "sin"^(2)theta, 4"cos" 6 theta), ("cos"^(2)theta, 1+"sin"^(2)theta, 4"cos"6theta), ("cos"^(2)theta, "sin"^(2)theta, 1+4"cos"6theta):}| = 0, is

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

The value of log_(sec30^(@))(cos^2 6 7^(@)+cos^2 5 3^(@)+cos6 7^(@)*cos5 3^(@)) is equal to

Find (I ) cos^(-1) (-1/sqrt(2)) (ii ) cos^(-1) ( cos (- pi/3)) (iii) cos^(-1) ( cos ((7 pi )/(6 )))

sin[tan^(-1)("tan"(7pi)/6)]+cos[cos^(-1)("cos"(7pi)/3)] = ____

The value of cos^(-1)(-(sqrt3)/2)+cos^(-1)(cos\ (7pi)/6) is