Calculus help...derivatives

[Lilly]

hi,
i know this problem has to do with derivatives and i'm sure its easy, but for some reason i just can't figure it out...
Find equations of both lines through the point (2,-3) that are tangent to the parabola y= x^2 + x

help please...i know the derivative is 2x + 1 ....and that the 2 equations will be linear and pass through the point above, obviously...just not sure where to go from there. :blushing:

[Himura Kenshin]

This is differentiation, you have dy/dx =2x+1.then substitute the x=2 in the dy/dx,then you will find that dy/dx =5(that is the gradient of the tangent)


y-(-3) =3(x-2)
y+3 = 3x-6
y= 3x-9 (equation of the tangent)

The othe equation you mention may be the normal for the curve.Use formula

m1 x m2 =-1

then you can solve the question.