यदि `A = 30^(@) ` तो दिखाइए कि :
` sin 3A = 3 sin A - 4 sin^(3) A`

Explanation

`L.H.S. = sin 3A = sin (3 xx 30^(@)) = sin 90^(@) = 1 `
R.H.S. = ` 3 sin A - 4 sin^(3) A = 3 sin 30^(@) - 4 sin^(3) 30^(@)`
` = 3 ((1)/(2)) - 4 ((1)/(2))^(3) = (3)/(2) - (4)/(8) = (3)/(2) - (1)/(2) = (2)/(2) = 1`
` therefore ` L.H.S. = R.H.S