Use the properties of the trigonometric functions to find the exact value, without using a calculator

Question

2 tan^(2) (38 degrees) - 2 sec^(2) (38 degrees)

Answer 1

2 tan² 38 - 2 sec² (38)

2 tan² 38 - 2(1 + tan² 38) Pythagorean Identity

2 tan² 38 - 2 - 2 tan² 38

-2