If an angle is in the second quadrant and its reference angle is (\frac{5\pi}{18}), what is its principal angle?

Question

Answer and explanation

Correct answer: (\frac{13\pi}{18})

In the second quadrant, the principal angle is (\pi-\alpha). Hence (\pi-\frac{5\pi}{18}=\frac{13\pi}{18}).

What is the correct answer to this question?

(\frac{13\pi}{18})

Why is this the correct answer?

In the second quadrant, the principal angle is (\pi-\alpha). Hence (\pi-\frac{5\pi}{18}=\frac{13\pi}{18}).

Which subject and chapter does this question cover?

This is a Class 12 Mathematics question. Chapter: Trigonometric Functions. Topic: Angles.