सिद्ध करें की `cos (n+1)x*cos(n-1)x+sin(n+1)x*sin(n-1)x=cos2x`.

Prove that (i) cos (n + 2) x cos (n+1) x +sin (n+2) x sin (n+1) x = cos x) (ii) " cos " .((pi)/(4)-x) " cos " .((pi)/(4)-y) " - sin " ((pi)/(4)-x ) " sin " ((pi)/(4) -y) =" sin " (x+y)

D(cos^(-1)x+sin^(-1)x)^(n)=

sin(n+1)xsin(n+2)x+cos(n+1)xcos(n+2)x=cosx

sin(n+1)xsin(n+2)x+cos(n+1)xcos(n+2)x=cosx

sin(n+1)x.cosnx-cos(n+1)x.sinnx= …………

The value of the determinant |a^(2)a1cos nx cos(n+1)x cos(n+2)x sin nx sin(n+1)x sin(n+2)x is independent of n(b)a(c)x(d) none of these

Prove that: sin(n+1)x sin(n+2)x+cos(n+1)x cos(n+2)x=c

Prove that sin(n+1)xsin(n+2)x+cos(n+1)xcos(n+2)x=cosx

Prove that sin(n+1)xsin(n+2)x+cos(n+1)xcos(n+2)x=cosx

The determinant Delta=|(a^2,a,1),(cos(nx),cos (n + 1) x,cos(n+2) x),(sin(nx),sin (n +1)x,sin (n + 2) x)| is independent of