If `x=cos 10^@ cos20^@ cos40^@` , then the value of x is

The absolute value of cos x is

If e^(cos x) -e^(-cos x) = 4 , then the value of cos x, is

The expression (cos6x+6cos4x+15cos2x+10)/(cos5x+5cos3x+10cosx) = lambdacosx , then the value of lambda is ___________.

If 5(tan^2x - cos^2x)=2cos 2x + 9 , then the value of cos4x is

If 5(tan^2x - cos^2x)=2cos 2x + 9 , then the value of cos4x is

The value of cos^(2)10^(@)-cos10^(@)cos 50^(@)+cos^(2)50^(@) is k/2 . The value of k is ________.

If cos^(2)30^(@)+cos^(2)45^(@)+cos^(2)60^(@)=x , then find the value of 'x'

If sin x=cos^2x ,\ then write the value of cos^2x\ (1+cos^2x)dot

if sin x + sin^2 x = 1 , then the value of cos^2 x + cos^4x is

if sin x + sin^2 x = 1 , then the value of cos^2 x + cos^4x is