Mathematics · Circles

JEE Main 2026 — 8 April, Evening Shift — Question 41

Consider the circle C : x2+y2−6x−8y−11=0x^{2}+y^{2}-6 x-8 y-11=0. Let a variable chord AB of the circle C subtend a right angle at the origin. If the locus of the foot of the perpendicular drawn from the origin on the chord AB is the circle x2+y2−αx−βy−γ=0\mathrm{x}^{2}+\mathrm{y}^{2}-\alpha \mathrm{x}-\beta \mathrm{y}-\gamma=0, then α+β+2γ\alpha+\beta+2 \gamma is equal to ____\_\_\_\_

Answer: 18

Numerical answer — enter this value.

Step-by-step solution

C:x2+y2−6x−8y−11=0\mathrm{C}: \mathrm{x}^{2}+\mathrm{y}^{2}-6 \mathrm{x}-8 \mathrm{y}-11=0 Eqn\mathrm{E}^{\mathrm{qn}} of chord AB y−k=−hk(x−h)\mathrm{y}-\mathrm{k}=-\frac{\mathrm{h}}{\mathrm{k}}(\mathrm{x}-\mathrm{h})

\mathrm{hx}+\mathrm{ky}=\mathrm{h}^{2}+\mathrm{k}^{2} \end{gathered}$$ Homogenising the eq ${ }^{\mathrm{n}}$ of the circle $\mathrm{x}^{2}+\mathrm{y}^{2}-6 \mathrm{x}\left(\frac{\mathrm{hx}+\mathrm{ky}}{\mathrm{h}^{2}+\mathrm{k}^{2}}\right)-8 \mathrm{y}\left(\frac{\mathrm{hx}+\mathrm{ky}}{\mathrm{h}^{2}+\mathrm{k}^{2}}\right)-11\left(\frac{\mathrm{hx}+\mathrm{ky}}{\mathrm{h}^{2}+\mathrm{k}^{2}}\right)^{2}=0$ coeff. of $x^{2}+$ coeff of $y^{2}=0$ $1-\frac{6 \mathrm{~h}}{\mathrm{~h}^{2}+\mathrm{k}^{2}}-11 \cdot \frac{\mathrm{~h}^{2}}{\left(\mathrm{~h}^{2}+\mathrm{k}^{2}\right)^{2}}+1-\frac{8 \mathrm{k}}{\mathrm{h}^{2}+\mathrm{k}^{2}}-11 \cdot \frac{\mathrm{k}^{2}}{\left(\mathrm{~h}^{2}+\mathrm{k}^{2}\right)^{2}}=0$ $2\left(h^{2}+k^{2}\right)-6 h-8 k-11=0$ $\mathrm{x}^{2}+\mathrm{y}^{2}-3 \mathrm{x}-4 \mathrm{y}-\frac{11}{2}=0$ $\therefore \alpha+\beta+2 \gamma=3+4+11=18$
Solution figure

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Exam
JEE Main 2026
Subject
Mathematics
Chapter
Circles
Topic
Introduction to Circles
Consider the circle C : x 2 +y 2 -6 x-8 y-11=0 . Let a variable chord… | JEE Main 2026 PYQ with Solution · DhiX AI