1.

The tangent to `y=a x^2+b x+7/2a t(1,2)`is parallel to thenormal at the point `(-2,2)`on the curve `y=x^2+6x+10 ,`then`a=-1`b. `a=1`c. `b=5/2`d. `b=-5/2`A. `a = 1`B. `a = -1`C. `b = (-15)/(2)`D. `b = (5)/(2)`

Answer» Correct Answer - A
`y = x^(2) + 6x + 10`
`:. (dy)/(dx) = 2x + 6`
`(dy)/(dx)|(-2,2) = 2`
`:.` slope of Normal,`m = - 1//2`
`:. y = ax^(2) + bx + (7)/(2)`
Passes through `(1,2) rArr a+ b = -3//2`…..(1)
Also `(dy)/(dx)|(1,2) = 2a + b`
`rArr - (1)/(2) = 2a + b`......(2)
`[1]` and [2] `rArr a = 1 , b = -5//2`


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