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\leftline{Mathematics 241 -- Multivariable Calculus}
\leftline{Quiz 6 -- October 29, 2010}
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\leftline{Your Name: $\underline{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }$}
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Let $f(x,y) = \cos(x + y) + \sin(x - y)$.
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A) (10) Find the directional derivative $D_{(\sqrt{3}/2,1/2)} f(\pi/2,\pi/2)$.
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B) (10) Find the tangent plane to $z = f(x,y)$ at $(\pi/2,\pi/2,-1)$.
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