Q. 13.8( 5 Votes )

If cos–1 x/2 + cos–1y/3 = a, then prove that 9x2–12xy cos a + 4y2 = 36 sin2 a.

Answer :



We know that, Formula


Now lets take square of both side, we get

Hence Proved

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Solve the following equation for x :

Mathematics - Board Papers