Mathematical Verifications | MCQs

Explanation

Let's evaluate each option:

1. sin² 60⁰ + cos² 60⁰ = 1

sin 60⁰ = √3/2, cos 60⁰ = 1/2

(√3/2)² + (1/2)² = 3/4 + 1/4 = 1

2. sin² 45⁰ + cos² 45⁰ = 1

sin 45⁰ = cos 45⁰ = 1/√2

(1/√2)² + (1/√2)² = 1/2 + 1/2 = 1

3. sin² 45⁰ − cos² 45⁰ = 0

(1/√2)² - (1/√2)² = 1/2 - 1/2 = 0

Explanation

Given the equation:

78.36 = 78.36xy

Dividing both sides by 78.36:

1 = xy

The only option that satisfies xy = 1 is:

x = 1 and y = 1

Since 1 × 1 = 1.

The answer is x = 1 and y = 1.