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surface of a spherical planet
you just discovered its circumference, that is the input.

14 years ago

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De-dupe
Remove all the redundant elements in a vector, but keep the first occurrence of each value in its original location. So if a =...

14 years ago

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Elapsed Time
Given two date strings d1 and d2 of the form yyyy/mm/dd HH:MM:SS (assume hours HH is in 24 hour mode), determine how much time, ...

14 years ago

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Distance walked 1D
Suppose you go from position 7 to 10 to 6 to 4. Then you have walked 9 units of distance, since 7 to 10 is 3 units, 10 to 6 is 4...

14 years ago

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Remove the vowels
Remove all the vowels in the given phrase. Example: Input s1 = 'Jack and Jill went up the hill' Output s2 is 'Jck nd Jll wn...

14 years ago

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Factorize THIS, buddy
List the prime factors for the input number, in decreasing order. List each factor only once, even if the factorization includes...

14 years ago

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matlab coding
OK, the question becomes more concrete now. Since you have A0 and A1, then you can do A = [A0 A1]; B = [A0*A0' A1*A1']; ...

14 years ago | 0

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Plot of 3D Matrix
You can |mesh| or |surf| doc mesh doc surf

14 years ago | 0

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Numerically solve for x in a polynomial equation
Write the polynomial as a*x^3+b*x^2+c*x+d-y Then you can use |fzero| to solve x. doc fzero

14 years ago | 1

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How do i intergrate a signal (sinewave)?
|int| is the symbolic toolbox integration. There are many numerical integration methods in MATLAB, just pick one of them. d...

14 years ago | 0

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frequency ulation
You can do an FFT to the output of the mixer to find the beat frequency. You can then convert beat frequency to the range using ...

14 years ago | 0

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Change Pixel intensity value
Say your image is |x|, x(x<0) = 0;

14 years ago | 0

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signal processing
You can us |xcorr| to do both auto and cross correlation, e.g., xcorr(x,x) xcorr(x,y) doc xcorr Auto correlation ...

14 years ago | 0

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Arrange Vector in descending order
If x=[0,3,4,2,1] then y=[4,3,2,1,0]

14 years ago

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Remove DC
Input x is the sampled signal vector, may have both AC and DC components. Output y should not contain any DC component. Examp...

14 years ago

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Find the sum of the elements in the "second" diagonal
Find the sum of the elements in the diagonal that starts at the top-right corner and ends at the bottom-left corner.

14 years ago

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Swap the input arguments
Write a two-input, two-output function that swaps its two input arguments. For example: [q,r] = swap(5,10) returns q = ...

14 years ago

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Omit columns averages from a matrix
Omit columns averages from a matrix. For example: A = 16 2 3 13 5 11 10 8 9 7 ...

14 years ago

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Is my wife right? Now with even more wrong husband
Again, as in "Is my wife right?" ( <http://www.mathworks.com/matlabcentral/cody/problems/149-is-my-wife-right> ), answer 'yes' r...

14 years ago

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area under curve for just 1 period
There are many integration methods in MATLAB, just pick one of them. doc quad doc quadl doc integral I'll use |qu...

14 years ago | 0

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Algorithm used in [d,l] = bwdist(I)
You can look at the references listed in Algorithm section of the doc doc bwdist

14 years ago | 0

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Gaussian Distribution
This is really just plotting an equation, for practical purpose, you can plot from -4*sd to 4*sd. Let's say mu is the mean, ...

14 years ago | 1

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non zero elements above 70 and below -70 zero
Use logical index x(x>70 | x<-70)=0

14 years ago | 0

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Histogram Peak
You can use |findpeaks| function in Signal Processing Toolbox doc findpeaks

14 years ago | 0

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Solved

Project Euler: Problem 1, Multiples of 3 and 5
If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23...

14 years ago

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Create times-tables
At one time or another, we all had to memorize boring times tables. 5 times 5 is 25. 5 times 6 is 30. 12 times 12 is way more th...

14 years ago

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Reverse the vector
Reverse the vector elements. Example: Input x = [1,2,3,4,5,6,7,8,9] Output y = [9,8,7,6,5,4,3,2,1]

14 years ago

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exponential random draws and the seed
What's your version of MATLAB? setGlobalStream is introduced in R2011a, try RandStream.setDefaultStream(s)

14 years ago | 0

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making a function work
Maybe the path is messed up, what is 'ThePathName'? I'd suggest to put calc_avg on the path, then cd to the directory where the ...

14 years ago | 1

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Using find command on each term in a vector
Not really a syntax for find, but take advantage of arrayfun a = -10:10; b = 22*rand(1,30)-11; c = arrayfun(@(x) find...

14 years ago | 0

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