AP EAMCET2015MathematicsCircle
The sum of the minimum and maximum distance of the point (4,-3) to the circle x^2+y^2+4 x-10 y-7=0 , is
Options
- A10
- B12
- C16
- D20
Correct answer
D. 20
Step-by-step solution
Let the given point be P(4,-3) and the given circle is x^2+y^2+4 x-10 y-7=0 Centre of circle = C (-2,5) Radius = (-2)^2+(5)^2+7 = 4+25+7 = 36 =6 Maximum distance, a=C P+r Minimum distance, b=C P-r Sum of the maximum and minimum distance, a+b=C P+r+C P-r=2 C P and C P= (-2-4)^2+(5+3)^2 = 36+64 = 100 =10 Thus, a+b=2 C P=2 10=20