Question

Radius of the circle x² + y² + 2x cos q + 2y sin q – 8 = 0 is –

• A. 1
• B. 3
• C. $2\sqrt{3}$
• D. $\sqrt{10}$

Answer 1

Answer: (B)

3

Answer 2

g = cosq, f = sinq, c = –8

r = $\sqrt{g^{2} + f^{2} - c}$

= $\sqrt{\cos^{2}\theta + \sin^{2}\theta + 8}$

= 3