How do you solve cot^2xcsc^2x-cot^2x=9 for 0<=x<=2pi?

1 Answer
Aug 8, 2016

x in {pi/3, 2pi/3, 4pi/3, 5pi/3} sub [0,2pi].

Explanation:

cot^2xcsc^2x-cot^2x=9

:. (csc^2x-1)cot^2x=9

:.cot^2x*cot^2x=9

:. cot^4x=9

:. cotx=+-sqrt3

:. tanx=+-1/sqrt3=tan(+-pi/6)

:. x in {npi+-pi/3 ; n in ZZ}

:. x in {pi/3, 2pi/3, 4pi/3, 5pi/3} sub [0,2pi].