1.

The point(s) on the line x = 2 from which the tangents drawn to the circle x2 + y2 = 16 are at right angles is (are)(a)  (2, -2√5) (b)  (2, 2√5)(c)  (2, 2√7)(d)  (2, -2√7)

Answer»

Correct option (a,d)

Explanation :

If the tangents drawn are at right angles, the points must be the intersection of the line x = 2 with the director circle x2 + y2 = 32 of the circle x2 + y2 = 16. Substituting x + 2 in x2 + y2 = 32, we have

y2 = 28 or y = ±2√7

Therefore, the points are (2, 27 ) and (2, -2√7).



Discussion

No Comment Found

Related InterviewSolutions