Question

solve it step by step​

Answer 1

sec^2 theta = tan^2 theta +1

putting this in equation

15 tan^2 theta + 4 sec^2 theta = 23

15 tan^2 theta + 4 ( tan^2 theta + 1) = 23

15 tan^2 theta + 4 tan^2 theta + 4 =23

19 tan^2 theta = 23- 4 = 19

tan^2 theta = 19/19 = 1