If cos = , then 2sec2 + 2tan2 - 6 equals:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 1
cos =
⇒B = 2, H = 3
By Pythagoras theorem, 32 = P2 + 22
P2 = 9 - 4
So, P =
sec2θ = (3/2)2 = 9/4
2sec2θ = 2 × 9/4 =9/2
tanθ = /2
tan2θ = (/2)2 = 5/4
2tan2θ = 5/2
2sec2θ + 2tan2θ − 6 = 9/2 + 5/2 − 6 = 1