1.

The number of common tangent(s) to the circles `x^2+y^2+2x+8y-23=0`and `x^2+y^2-4x-10 y-19=0`is1 (b) 2(c) 3 (d)4A. `1`B. `2`C. `3`D. `4`

Answer» Correct Answer - C
the number ber of …………
`x^(2)+y^(2)+2x+8y-23= 0` ………..(1)
`x^(2)+y^(2)-4x-10y+19 = 0` ………..(2)
`c_(1) -= (-1, -4)` , `r_(1) = sqrt(1+16+23) = 2sqrt(10)`
`c_(2)-= (2, 5)` , `r_(2)= sqrt(4+25-19) = sqrt(10)`
Here `c_(1)c_(2) = sqrt(9+81), r_(1)+r_(2)= 3sqrt(10)`
Hence circles touch each other externally So there are 3 common tangent


Discussion

No Comment Found

Related InterviewSolutions