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gibson:teaching:fall-2014:math445:hw5

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 gibson:teaching:fall-2014:math445:hw5 [2014/10/13 12:48]gibson gibson:teaching:fall-2014:math445:hw5 [2014/10/14 12:39] (current)gibson Both sides previous revision Previous revision 2014/10/14 12:39 gibson 2014/10/13 12:49 gibson 2014/10/13 12:48 gibson 2014/10/13 12:48 gibson 2014/10/13 12:48 gibson 2014/10/13 12:47 gibson 2014/10/13 12:47 gibson created Next revision Previous revision 2014/10/14 12:39 gibson 2014/10/13 12:49 gibson 2014/10/13 12:48 gibson 2014/10/13 12:48 gibson 2014/10/13 12:48 gibson 2014/10/13 12:47 gibson 2014/10/13 12:47 gibson created Line 3: Line 3: Main concept for this homework: the ''​for''​ loop. Main concept for this homework: the ''​for''​ loop. - 1. Write a function ''​mymean''​ that uses a ''​for''​ loop to compute the mean of the elements of its input vector. Test that it's correct by comparing ​to Matlab'​s built-in ''​mean''​ function on a random vector. ​ + 1. Write a function ''​mymean''​ that uses a ''​for''​ loop to compute the mean of the elements of its input vector, according ​to the formula - 2. Write a function ''​mystd''​ that uses a ''​for''​ loop to computes the standard deviation of the elements of its input vector. Test by comparison to Matlab'​s built-in ''​std''​ function on a random vector. + \begin{eqnarray*} + \text{mean}(x) = \frac{1}{N} \sum_{i=1}^N x_i + \end{eqnarray*} + + where N is the number of elements in the vector. Test that your code is correct by comparing to Matlab'​s built-in ''​mean''​ function on a random vector. + + 2. Write a function ''​mystd''​ that uses a ''​for''​ loop to computes the standard deviation of the elements of its input vector. + \begin{eqnarray*} + \text{std dev}(x) = \sqrt{\frac{1}{N-1} \sum_{i=1}^N (x_i - \bar{x})^2 + \end{eqnarray*} + where $\bar{x}$ is the mean of $x$. Test by comparison to Matlab'​s built-in ''​std''​ function on a random vector. 3. Write a script that produces a 10 x 10 multiplication table whose first three lines are 3. Write a script that produces a 10 x 10 multiplication table whose first three lines are Line 24: Line 34: \begin{eqnarray*} \begin{eqnarray*} - y_i = sum_{j=1^N} A_{ij} x_j + y_i = \sum_{j=1}^N A_{ij} x_j \end{eqnarray*} \end{eqnarray*} Line 33: Line 43: \begin{eqnarray*} \begin{eqnarray*} - C_{ij} = sum_{j=1^N} A_{ik} C_{kj} + C_{ij} = \sum_{k=1}^N A_{ik} C_{kj} \end{eqnarray*} \end{eqnarray*} where //N// is the number of columns of //A//. If A is //M x N// and //B// is //N x P//, then //C// is //M x P//. If //A// and //B// do not have compatible dimensions, print an error message and return a //0 x 0// matrix. ​ where //N// is the number of columns of //A//. If A is //M x N// and //B// is //N x P//, then //C// is //M x P//. If //A// and //B// do not have compatible dimensions, print an error message and return a //0 x 0// matrix. ​ -