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math121a-f23:hw_8 [2023/10/20 22:06] pzhou |
math121a-f23:hw_8 [2023/10/24 21:43] (current) pzhou |
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Suppose you are given a function on an interval, . Such function can be expressed as a sum of 'sine waves' and cosine waves and constant | Suppose you are given a function on an interval, . Such function can be expressed as a sum of 'sine waves' and cosine waves and constant | ||
- | f(x) = a_0 + \sum_{n=1}^\infty a_n \cos(n \pi x) + b_n \sin(n \pi x). | + | f(x) = a_0 + \sum_{n=1}^\infty a_n \cos(2n \pi x) + b_n \sin(2n \pi x). |
Can you figure out a way to determine the coefficients and ? | Can you figure out a way to determine the coefficients and ? | ||
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f(x) = \begin{cases} 1 & 0 < x < 1/2 \cr | f(x) = \begin{cases} 1 & 0 < x < 1/2 \cr | ||
0 & 1/2 \leq x \leq 1 | 0 & 1/2 \leq x \leq 1 | ||
- | \end{\cases} | + | \end{cases} |
+ | |||
find and plot the truncated Fourier series | find and plot the truncated Fourier series | ||
- | + | a_0 + a_1 \cos(2 \pi x) + b_1 \sin(2 \pi x). | |
- | How does the resemble your original given function? | + | How does this resemble your original given function? |
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And suppose . Can you solve for ? | And suppose . Can you solve for ? | ||
- | For the following problems, you need to apply Laplace transformation to the equation, and get the for the desired , and do the inverse Laplace transformation to get back the desired answer. | ||
3. Consider the following equation, for , | 3. Consider the following equation, for , |