Let \( \cos 6x = a\cos^6 x + b\cos^4 x + c\cos^2 x + d \) for any real number x, where a, b, c, d are real constants. Then the value of \( a + b + c \) is equal to
Step-by-step Solution:
Standard expansion of \(\cos 6x\) in powers of \(\cos x\) leads to coefficients whose sum \(a+b+c\) equals 2.