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#1 2006-01-10 14:49:07
- RickyOswaldIOW
- Member
- Registered: 2005-11-18
- Posts: 212
Tangent to Normal.
I've been working out the gradient (and whole equation) of the tangent of certain points on a curve but this new set of questions wants the equation of the normal. I figure I'd just work as I had been and get the equation of the tangent, then simply flip over the gradient and reverse the sign for the normal i.e.
tangent; y = 7x - 13
normal; y = -1/7x - 13
The full sum is as follows:
y = 2x^2 - 5x + 3 at (2, 1)
dy/dx = 6x - 5
12 - 5 = 7
(y - 1)/(x - 2) = 7
y - 1 = 7(x - 2) = 7x - 14
y = 7x - 13
and thus the normal; y = -1/7x - 13.
The book claims x + 3y = 5
Aloha Nui means Goodbye.
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#2 2006-01-10 15:25:04
- Ricky
- Moderator
- Registered: 2005-12-04
- Posts: 3,791
Re: Tangent to Normal.
dy/dx = 6x - 5
dy/dx = 4x - 5, slope at (1, 2) is 3
Try it now.
"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."
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#3 2006-01-10 15:28:08
- RickyOswaldIOW
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- Registered: 2005-11-18
- Posts: 212
Re: Tangent to Normal.
Aloha Nui means Goodbye.
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#4 2006-01-10 15:32:54
- Ricky
- Moderator
- Registered: 2005-12-04
- Posts: 3,791
Re: Tangent to Normal.
Don't worry about it, on a math test, I wrote:
2x = 2
x = 2
"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."
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