Question bank/JEE Main/Mathematics

JEE MainMathematicsToughCircles

If C1:x2+y2=(3+22)2C_{1}:x^{2} + y^{2} = (3 + 2\sqrt{2})^{2}is a circle and PA
and PB are a pair of tangents on C_1,where P is any point on the

director circle of C_1 then the radius of the smaller circle which

touches C_1 externally and also the two tangents PA and PB is;fn
C1:x2+y2=(3+22)2C_{1}:x^{2} + y^{2} = (3 + 2\sqrt{2})^{2},d o`Ùk gS rFkk PA vkSj
PB ij tgk¡ P, C_1 o`Ùk ij dksbZ

fcUnq gS rc NksVs o`Ùk dh f=T;k gksxh tks C_1 dks cká rFkk nks PA rFkk PB

Show answer and solution
AQ=3+22AQ = 3 + 2\sqrt{2}
PQ=32+4PQ = 3\sqrt{2} + 4
Let r be the required radius

Then rc

32+4=3+22+r+r23\sqrt{2} + 4 = 3 + 2\sqrt{2} + r + r\sqrt{2}
r = 1

Source: Grass-G / M-26 Mathematics Paper 1 15 Jan.docx

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