Question

If at x = 1, y = 2x is tangent to the parabola $y=a{x}^2+bx+c$, then respective values of a, b, c possible are

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

for x =1, y = a + b + c

Tangent at $(1,a+b+c)is\frac{1}{2}(y+a+b+c)=ax+\frac{b}{2}(x+1)+c$

Comparing with y = 2x, c = a, b = 2(1-a)
Which are true for choice (1) only