सिद्ध कीजिए
` 3cos ^(-1) x = cos ^( -1) ( 4x ^ 3 - 3x ) ` .

Explanation

मानलों ` cos ^( -1) x = theta `
` therefore x = cos theta `
अब ` cos 3 theta = 4 cos ^( 3 ) theta - 3 cos theta = 4 x ^ 3 - 3x `
` therefore 3 theta = cos ^( -1 ) ( 4x ^ 3 - 3x ) `
अतः ` 3 cos ^( -1) x = cos ^( -1 ) ( 4x ^ 3 - 3 x) `