(New page: == Homework 4 collaboration area == Back to the MA 530 Rhea start page To Rhea Course List) |
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== Homework 4 collaboration area == | == Homework 4 collaboration area == | ||
| + | Problem 7 hint: | ||
| + | <math>e^{\pm f(z)}</math> | ||
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| + | Problem 10 hint: | ||
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| + | Parametrize the circular part of the boundary via | ||
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| + | <math>C_r:\quad z(t)=Re^{it}, 0<t<\pi/4.</math> | ||
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| + | You need to show that | ||
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| + | <math>I_R := \int_{C_R}e^{-z^2}\ dz\to 0</math> | ||
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| + | as R goes to infinity. You won't be able to use the standard estimate to do this. Write out the definition of the integral to find that | ||
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| + | <math>|I_R|\le\int Re^{-R^2\cos(2t)}\,dt</math> | ||
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| + | and use freshman calculus ideas to show that this integral tends to zero. (Don't hit it with the big stick, the Lebesgue Dominated Convergence Theorem.) | ||
Revision as of 05:06, 9 February 2011
Homework 4 collaboration area
Problem 7 hint:
$ e^{\pm f(z)} $
Problem 10 hint:
Parametrize the circular part of the boundary via
$ C_r:\quad z(t)=Re^{it}, 0<t<\pi/4. $
You need to show that
$ I_R := \int_{C_R}e^{-z^2}\ dz\to 0 $
as R goes to infinity. You won't be able to use the standard estimate to do this. Write out the definition of the integral to find that
$ |I_R|\le\int Re^{-R^2\cos(2t)}\,dt $
and use freshman calculus ideas to show that this integral tends to zero. (Don't hit it with the big stick, the Lebesgue Dominated Convergence Theorem.)
