Find the equation of the normal to the curve y= 2x\(^2\) - 5x + 10 at P(1, 7).

  • A y+x-3 =0
  • B y-x+6=0
  • C y - x - 6=0
  • D y -x+ 3 =0
waec 2021furthermathematics

The correct answer is C. y - x - 6=0

From y= 2x- 5x 10 ; dy/dx= 4x-5

But at (1, 7); m\(_1\) = (dy/dx)\(_{1,7}\)

= 4(1) - 5 = -1

Using m\(_1\)m\(_2\),= -1; m\(_2\) = 1.

Gradient m\(_2\), of normal at (1,7) is 1.

Using y - y\(_1\) = m(x - x\(_1\))

y - 7 = 1(x - 1) ;

y - 7 = x - 1

y - x - 6 = 0

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