Solve for x 0<x<360

Sep 2019
4
0
G
Hi

Looking for a pointer on where Im going wrong:

2sec2x – 5tanx – 5
2 (tan2x + 1) – 5tanx – 5
2tan2x – 5tanx -3
tanx = k

2k2-5k-3

5+/-sqrt4 – 4.2.-3 / 4 = 2.573 or -0.073
tanx = 2.573 tanx = 0.0073
x = 68.76 x= 4.175
textbook saying should be 30 and 150
 
Sep 2019
4
0
G
ignore the last part about the textbook looked on the wrong page correct page says answer should be 153.435 ; 333.435 ; 71.565 ; 251.565
 
Jun 2013
1,110
590
Lebanon
Solving

$$2k^2-5k-3=0$$

we get $k=-\frac{1}{2}$ and $k=3$