Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Trigonometry

Question:

In a ΔABC right angled at B, AB = 8 unit and AC = 10 unit. What is the value of $\sin^2θ-\cos^2θ$ where θ is ∠ACB?

Options:

$\frac{9}{25}$

$\frac{7}{25}$

$\frac{22}{25}$

$\frac{16}{25}$

Correct Answer:

$\frac{7}{25}$

Explanation:

In a ΔABC right angled at B, AB = 8 unit and AC = 10 unit

AC^2 = AB^2 + BC^2

100 = 64 + BC^2

BC = 6

SinB = 8/10 = 4/5

Sin2B = 16/25

CosB = 6/10 = 3/5

Cos2B = 9/25

Sin2B - Cos2B = 16/25 - 9/25 = 7/25

 

The correct answer is Option (2) → $\frac{7}{25}$