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Asked by Dhurgham Kadhim on 15 Apr 2012

Use the Lagrange mulipliers to find the points on the parabola y=x^2+2x which are the closest to the point(-1,0).

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Answer by bym on 16 Apr 2012

Accepted answer

here is a nudge to solving your problem

syms x y L d = ??? % for you to fill out; distance from (-1,0) g = d+L*(x^2+2*x-y) % constraint for given parabola % additional operations here

show some effort, and some additional help may be forthcoming

Answer by Richard Brown on 15 Apr 2012

This is not a Matlab question, it's a calculus homework problem. Define a function f(x,y) that you want to minimise, a constraint c(x,y) = 0, and then solve c(x,y) = 0, together with

grad f = lambda grad c

for x, y, and lambda.

Richard Brown on 16 Apr 2012

It's pretty straightforward to solve by hand - I recommend you do it that way, you'll learn more if you do.

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