19ans is (b),,,a circle
use a√(1+m2) = c ......if a st line y=mx + c touches a circle x2 + y2 =a2
Ques) If x/ p + y/q = 1 touches the circle x2 + y2 = a2 , then the point (1 / p , 1/q) lies on a /an
(a) Straight line (b) Circle (c) Parabola (d)Ellipse
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4 Answers
1919just look at my stupidity [2]
i got a2h2 + a2k2 = 1 (h=1/p and k=1/q) and i marked ellipse...shit ,,,i feel like kicking myself !!!
edited it...sorry for the lackluster !
1ans is b circle , eqn of line will be qx+py-pq=0 .dist of this line from (0,0) is a. so pq/√(p2+q2) =a or (1/p2+1/q2)=1/a2 we can see that dist of 1/p,1/q from (0,0) is constant.