Question

(sen a + cosec a)^2 = sen^2 a + cot^2 a +3

Answer 1

$(Sen \alpha +Csc \alpha )^{2} = Sen^{2} \alpha +2(Sen \alpha)(Csc \alpha)+Csc^{2} \alpha= \\ Sen^{2} \alpha+2+Csc^{2} \alpha=Sen^{2} \alpha+3+Csc^{2} \alpha-1= \\ Sen^{2} \alpha+3+Cot^{2} \alpha$