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If the line x+y=a touches the parabola y...

If the line `x+y=a` touches the parabola `y=x-x^2,` then find the value of `adot`

A

0

B

1

C

`-1`

D

None of these

Text Solution

Verified by Experts

The correct Answer is:
2
Eliminating y, we have `a- x= x- x^(2)`
or `x^(2) - 2x + a =0`. Since the line touches the parabola, we must have equal roots . Therefore , `4- 4a =0 ` or `a=1`
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