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Math Help - Need some maths help. I am stuck!

  1. #1
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    Need some maths help. I am stuck!

    A curve has the equation y=x^2-3x+4

    a) Find an equation of the normal to the curve at the point A (2,2).

    The normal to the curve at A intersects the curve again at the point B.

    b) Find the coordinates of the point B.


    Any one know how to do this?
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  2. #2
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by Colin_m View Post
    A curve has the equation y=x^2-3x+4

    a) Find an equation of the normal to the curve at the point A (2,2).

    The normal to the curve at A intersects the curve again at the point B.

    b) Find the coordinates of the point B.


    Any one know how to do this?
    hint: the normal line is the line perpendicular to the tangent line.

    do you know how to find the tangent line?
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  3. #3
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    do i need to find the gradient then use y=mx+c?
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    Quote Originally Posted by Colin_m View Post
    do i need to find the gradient then use y=mx+c?
    Yes, but what is the relationship between the slopes of two perpendicular lines?

    -Dan
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  5. #5
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    there the same
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    Quote Originally Posted by Colin_m View Post
    there the same
    No, if you have two (non-vertical) perpendicular lines their slope products is -1.
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  7. #7
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    i am confused now. So how will i start off working this out?

    A curve has the equation y=x^2-3x+4

    a) Find an equation of the normal to the curve at the point A (2,2).

    The normal to the curve at A intersects the curve again at the point B.

    b) Find the coordinates of the point B.


    Any one know how to do this?
    Follow Math Help Forum on Facebook and Google+

  8. #8
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by Colin_m View Post
    i am confused now. So how will i start off working this out?

    A curve has the equation y=x^2-3x+4

    a) Find an equation of the normal to the curve at the point A (2,2).

    The normal to the curve at A intersects the curve again at the point B.

    b) Find the coordinates of the point B.


    Any one know how to do this?
    Find your gradient for the function at x = 2. That's the slope of the line tangent to your curve at x = 2. To find the slope of the line normal to this you take the slope of your normal line as -1/gradient.

    -Dan
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  9. #9
    is up to his old tricks again! Jhevon's Avatar
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    by the way, the formula for the slope at any value of x is given by the derivative
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