1.

If the two circles `(x+1)^2+(y-3)=r^2 and x^2+y^2-8x+2y+8=0` intersect in two distinct point,then (A) `r > 2` (B) `2 < r < 8` (C) `r < 2` (D) `r=2`A. `2ltrlt8`B. `rlt2`C. r = 2D. `r gt 2`

Answer» Correct Answer - A
As, the two circle intersect in two distinct points.
`rArr " Distance between centre lies between " |r_(1)-r_(2)| and |r_(1)+r_(2)|`.
i.e. `|r-3|ltsqrt((4-1)^(2)+(-1-3)^(2))lt|r+3|`
`rArr |r-3|lt5lt|r+3|rArrlt8 or rgt2`
`therefore 2ltrlt8`


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