सिद्ध कीजिए : `((1)/(sec^(2) theta - cos^(2) theta)+(1)/(" cosec "^(2) theta - sin^(2) theta )) . sin^(2) theta cos^(2) theta = (1 - sin^(2) theta cos^(2)theta)/(2 + sin^(2) theta cos^(2) theta)`