Chapter 13: Problem 12
Construct a function whose level curve \(f=0\) is in two separate pieces.
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Chapter 13: Problem 12
Construct a function whose level curve \(f=0\) is in two separate pieces.
These are the key concepts you need to understand to accurately answer the question.
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Find the velocity \(v\) and the tangent vector \(T\). Then compute the rate of change \(d f / d t=\operatorname{grad} f \cdot \mathbf{v}\) and the slope \(d f / d s=\operatorname{grad} f \cdot \mathbf{T}\). \(f=x^{2}+y^{2} \quad x=t \quad y=t^{2}\)
Choose \(c>0\) so that \(f=x^{2}+x y+c y^{2}\) has a saddle point at \((0,0) .\) Note that \(f>0\) on the lines \(x=0\) and \(y=0\) and \(y=\) \(x\) and \(y=-x,\) so checking four directions does not confirm a minimum.
Maximize and minimize \(f=x+\sqrt{3} y\) on the circle \(x=\) \(\cos t, y=\sin t\).
Find \(f_{x}, f_{y}, f_{x x}, f_{x y}, f_{y y}\) at the basepoint. Write the quadratic approximation to \(f(x, y)-\) the Taylor series through second order terms: \(f=e^{x+y}\) at (1,1)
Allow inequality constraints, optional but good. A wire \(40^{\prime \prime}\) long is used to enclose one or two squares (side \(x\) and side \(y\) ). Maximize the total area \(x^{2}+y^{2}\) subject to \(x \geqslant 0, y \geqslant 0,4 x+4 y=40\).
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