If `cos^(-1)x/a+cos^(-1)y/b=alpha` , then `(x^2)/(a^2)-(2x y)/(a b)cosalpha+(y^2)/(b^2)=` `s in^2alpha` (b) `cos^2alpha` (c) `t a n^2alpha` (d) `cot^2alpha`

If cos^(-1)(x/a)+cos^(-1)(y/b)=alpha, prove that (x^2)/(a^2)-2(x y)/(a b)cosalpha+(y^2)/(b^2)=sin^2alpha

If cos^(-1)(x/a)+cos^(-1)(y/b)=alpha, prove that (x^2)/(a^2)-2(x y)/(a b)cosalpha+(y^2)/(b^2)=sin^2alpha

If cos^(-1)x/a+cos^(-1)y/b=alpha, prove that (x^2)/(a^2)-2(x y)/(a b)cosalpha+(y^2)/(b^2)=sin^2alpha

If cos^(-1)(x/a) + cos^(-1) (y/b) = a show that : (x^2)/(a^2) - (2xy)/(ab) cos alpha + (y^2)/(b^2) = sin^(2) alpha .

If cos^(- 1)x-cos^(- 1)(y/2)=alpha then 4x^2-4xycosalpha+y^2=

If cos^(-1)x-cos^(-1)y/2=alpha,t h e n4x^2-4x ycosalpha+y^2 is equal to 4 (b) 2sin^2alpha (c) -4sin^2alpha (d) 4sin^2alpha

If cos^(-1) (x/2) + cos^(-1) (y/3) =alpha then prove that 9x^2-12xycosalpha+4y^2=36sin^2alpha .

If cot^(-1)(sqrt(cosalpha))-tan^(-1)(sqrt(cosalpha))=x , then sinx is tan^2alpha/2 (b) cot^2alpha/2 (c) tan^2alpha (d) cotalpha/2

If theta is eliminated from the equations x=a"cos"(theta-alpha) and y=bcos(theta-beta), then (x^2/a^2)+(y^2/b^2)-(2xy)/(ab)cos(alpha-beta) is equal to (a) sec^2(alpha-beta) (b) cos e c^2(alpha-beta) (c) cos^2(alpha-beta) (d) sin^2(alpha-beta)

f(alpha,beta) = cos^2(alpha)+ cos^2(alpha+beta)- 2 cosalpha cosbeta cos(alpha+beta) is