if 
then cos θ is equal to:
Show answer & explanation
Correct answer: A
Explanation
Correct answer is option 1 i.e. 2p/(1+p2)
|
Concept |
Understanding |
Application |
Fair calculation |
|
Sin x = perpendicular/hypotenuses Cos x = base/ hypotenuses
Pythagoras theorem Base2 = Hypotenuses2 – Perpendicular2
|
Given Sin θ = (p2-1)/(p2+1) By comparing Perpendicular = (p2-1) Hypotenuses = (p2+1)
|
Base2 = Hypotenuses2 – Perpendicular2 Base = 2p
Cos θ = 2p/(1+p2) |
Base2 = (p2+1)2 - (p2-1)2 = p4 + 1 + 2p2 – p4 - 1 + 2p2 = 4p2 So, Base = 2p |