Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

$(sin θ + cos θ)^2 = 2, 0° < θ < 90°$, then the value of θ is :

Options:

0

$\frac{\pi}{2}$

$\pi$

$\frac{\pi}{4}$

Correct Answer:

$\frac{\pi}{4}$

Explanation:

( sinθ + cosθ )² = 2

sin²θ + cos²θ + 2sinθ.cosθ = 2

{ we know, sin²θ + cos²θ  = 1 }

1 + 2sinθ.cosθ = 2 

{ 2sinθ.cosθ = sin2θ }

sin2θ = 1

sin2θ = sin90º                { sin90º = 1 }

2θ = 90º

θ = 45º

θ = \(\frac{π }{4}\)