Question

2. If 1 - tan20 = K2, then the value of (seco + tan30 , coseco) is equal to (1) V(1—62)3 (2) V(2-K²3 (3) V(3 – K2,3 (4) 1(2+ k?)3

JEE/Engineering Exams

Maths

Solution

4.0 (1 ratings)

( 1-tan ^{2} theta=k^{2} ) ( 1-left(sec ^{2} theta-1right)=k^{2} ) ( sec ^{2} theta=2-k^{2} ) ( sec theta=sqrt{2-k^{2}} ) ( =sec theta+tan ^{3} theta cdot sin theta cdot frac{1}{cos theta} sin theta ) ( =sec theta+tan ^{2} alpha cdot sec theta ) ( =sec thetaleft(1+tan ^{2} thetaright) ) ( =sec theta cdot sec ^{2} theta ) ( =intleft(2-k^{2}right)^{3} )