Question

cec^2x+?=1 ?＝啥求大神解答啊啊啊啊

Answer 1

cec?

是csc吧

csc^2x-1=1/sin^2x-1=(1-sin^2x)/sin^2x=cos^2x/sin^2x=cot^2x

所以csc^2x-cot^2x=1