Official papers

Official 2022 Paper 1 · Q12

Paper 1Functions & graphsAlgebra

A family of quadratic curves is given by

yk=2(x−k2)2+k22+4k+3y_k=2\left(x-\frac k2\right)^2+\frac{k^2}2+4k+3

where kk is any real number and yky_k is a function of xx.

All these curves are sketched, and the point with the lowest yy-coordinate among all the curves yky_k is (a,b)(a,b).

Find the value of a+ba+b.

A−1-1
B−3-3
C−5-5
D−7-7
E−9-9

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