Question

( sqrt{3}left(frac{2}{5} sin theta cdot cos thetaright)=2 cos ^{2} theta )
( u_{0}^{prime} cos 2 theta=2 cos ^{2} theta-1 )
( therefore sqrt{3} sin theta=cos theta )
( tan theta=frac{1}{sqrt{3}} Rightarrow theta=30^{circ} )

# 19. If 13 sin(20) = 1 + cos(20) then value of 0 will be : (1) 30° (2) 60° (3) 90° (4) 120°

Solution