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MathsMediumMCQ2015 · 04 Apr

Q70.The number of common tangents to the circles x2 + y2 −4x −6y −12 = 0 and x2 + y2 + 6x + 18y + 26 = 0 , is (1) 4 (2) 1 (3) 2 (4) 3

What This Question Tests

This question involves determining the number of common tangents between two circles by calculating their centers, radii, and the distance between their centers to compare with the sum/difference of radii.

Concepts Tested

Equation of a circleCenter and radius of a circleDistance between centersCondition for number of common tangents

Formulas Used

(x-h)^2 + (y-k)^2 = r^2

Distance formula d = sqrt((x2-x1)^2 + (y2-y1)^2)

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