Question

8. The length of the tangent from a point on
x2+y2+4x+8y-4=0 to 2x2+2y2+8x+16y+1=0 is
3
1) 3
2)
برا | M
3) 52
4) 312​

Answer 1

Answer:

3

Step-by-step explanation:

Centre of both circle, C 1 =(−1,−4);C2 =(2,5);

r 1 = 1+16+23 =2√10 ;

r 2 = 4+25−19 = 10 ;

Distance between their centres = C 1 C 2

= √9+18

= 3√10

⇒C1.C2 =r1+r 2

Since the distance between their centres = sum of their radii.

Hence, circles touch externally which gives us 3 tangents in common