[" (a) "x cos^(-1)((x)/(2))+cos^(-1)((x)/(3))=a" ,prove that "],[x^(2)-12xy cos a+4y^(2)=36sin^(2)a]

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

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//2+cos^(-1) y//3=theta," prove that "9x^(2)-12xy cos theta+4y^(2)=36sin^(2) theta

If cos^(-1)(x/2)+cos^(-1)(y/3) = theta , prove that 9x^2- 12xycostheta+ 4y^2= 36 sin^(2)theta

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

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

If cos^(-1)x+cos^(-1)y=theta show that x^(2)-2xy cos theta+y^(2)=sin^(2)theta

If "cos"^(-1)(x/y) +"cos"^-1(y/3)= theta, "prove that" 9x^2- 12xy "cos" theta +4y^2 =36 "sin"^2 theta .

If cos^(-1)(x)/(2)+cos^(-1)(y)/(3)=theta then the maximum of 9x^(2)-12xy costheta + 4y^(2) is