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← JEE Main 2022 · 25 Jun · Shift 1
MathematicsInteger+4 / -1Question 24 of 90

JEE Main 2022 · 25 Jun · Shift 1, Mathematics question 24

Let the abscissae of the two points P and Q be the roots of 2x2−rx+p=02x^2-rx+p=0 and the ordinates of P and Q be the roots of x2−sx−q=0x^2-sx-q=0. If the equation of the circle described on PQ as diameter is 2(x2+y2)−11x−14y−22=02\left(x^2+y^2\right)-11x-14y-22=0, then 2r+s−2q+p2r+s-2q+p is equal to ______.

Answer and worked solution

Official answer: 7

Diameter form. (x−x1)(x−x2)+(y−y1)(y−y2)=0(x-x_1)(x-x_2)+(y-y_1)(y-y_2)=0, i.e. x2−r2x+p2+y2−sy−q=0x^2-\frac r2x+\frac p2+y^2-sy-q=0.

Compare with x2+y2−112x−7y−11=0x^2+y^2-\frac{11}2x-7y-11=0: r=11r=11, s=7s=7, p2−q=−11\frac p2-q=-11.

Value. 2r+s−2q+p=22+7+2(p2−q)=29−22=72r+s-2q+p=22+7+2\left(\frac p2-q\right)=29-22=7.

Answer: 7