Madhyamik Trigonometry( Trigonometric Ratios and Identities ), Ganit Prakash Book Chapter-23.2 question no. 5.(iv)

Madhyamik Trigonometry, Trigonometric Ratios and Identities , Ganit Prakash Book Chapter-23.2 question no. 5.(iv), West Bengal Board Class 10 Trigonometry ,Wbbse Maths For Class 10