Question 252522
2 tan y + 5 cosy y = 0 for 0 < y < 6 
---------------------
Do you mean 2 tan y + 5 cosy = 0  ??
2sin/cos + 5cos = 0
2sin + 5cos^2 = 0
2sin +5(1-sin^2) = 0
-5sin^2 + 2sin + 5 = 0
Now it's a quadratic in sin(y)
Sub x for sin(y):
*[invoke solve_quadratic_equation -5,2,5]
Ignore the value >1
sin(y) =~-0.819804
y =~ -55 degs
or 305 degs, 235 degs
In radians, = 5.323, 4.102