cos9x cos7x=cos5x cos3x[-(pi)/(4)leqslant x leqslant(pi)/(4)]

cos9x cos7x=cos5x cos3x; -pi/4 leq x leq pi/4

cos9x cos7x = cos5x cos3x [-pi/4 le x le pi/4]

Prove that cos^-1 ((sin x + cos x )/(sqrt2)) = x - (pi/4), (pi/4) le x le ((5pi)/4)

cos^(-1)((sin x+cos x)/(sqrt(2))),(pi)/(4) lt x lt (5pi)/4

If f(x) = cos x cos 2x cos 4x cos (8x). cos 16x then find f' (pi/4)

If f(x) = cos x cos 2x cos 4x cos (8x). cos 16x then find f' (pi/4)

If f(x)=cos x cos2x cos4x cos(8x)*cos16x then find f'((pi)/(4))

If f(x) = cos x cos 2x cos 4x cos (8x). cos 16x then find f' (pi/4)

f(x)-cos5x+A cos4x+B cos3x+C cos2x+D cos xE and T-f(0)-f((pi)/(5))+f((3 pi)/(5))+......+f((8 pi)/(5))-f((9)/(4) then T