Answer:
Explanation:
cot²(3x)=y
y²-3y+2=0
y²-y-2y+2=0
y(y-1)-2(y-1)=0
(y-1)(y-2)=0
y=1,y=2
cot3x=1
tan 3x=1=tan (π/4)=tan (nπ+π/4)
3x=nπ+π/4=(4nπ+π)/4=(4n+1)π/4
x=(4nπ+1)π/12,n is an integer.
cot 3x=2
tan 3x=1/2
3x=tan^{-1}(1/2)≈26.57°+360n
x≈8.86°+120n