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

If cos ^(-1) .(x)/(a)+ cos ^(-1). (y)/(b) = theta then prove that (x^(2))/(a^(2)) -(2xy)/(ab) . cos theta+ (y^(2))/(b^(2)) = sin ^(2) theta .

Let cos^-1(x/a)+cos^-1(y/b)=alpha thenAnswer the following questions (A) x^2/a^2+y^2/b^2+(2xy)/(ab) cos alpha = sin^2 alpha (B) x^2/a^2-y^2/b^2+(2xy)/(ab) cos alpha = sin^2 alpha (C) x^2/a^2+y^2/b^2-(2xy)/(ab) cos alpha = sin^2 alpha (D) x^2/a^2-y^2/b^2-(2xy)/(ab) cos alpha = sin^2 alpha

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

If cos^(-1) x - cos^(-1). y/2= alpha ", then " 4x^(2) - 4xy cos alpha + y^(2) is equal to