1. 2 sin 2t − 3tan 2t = 0
2sin2t - 3sin2t / cos2t = 0
sin2t [ 2 - 3/cos2t] = 0
Set each factor to 0
sin2t = 0 and this occurs at n* pi/2 where n is an integer
For the second factor, we have
2 - 3/cos2t = 0
2 - 3sec(2t) = 0
sec(2t) = 2/3 and there is no solution to this
Here's a graph [in degrees ] .......https://www.desmos.com/calculator/x7dws0dxus
I assume that the second one is :
[6 cot t]^2 = 108
36cot^2 t = 108 divide both sides by 36
cot^2 t = 3 take the square root of both sides
cot t = ± sqrt (3)
For the first soluton, we have
cot t = sqrt(3) this occurs at pi/6 + n*pi where n is an integer
For the second solution, we have
cot t = - sqrt(3) this occurs at 5pi/6 + n*pi where n is an integer
Here's the graph [in degrees] : https://www.desmos.com/calculator/hbl4cuxc3a