David K

Last seen: 3 days ago

195 total contributions since 2015

I spend a lot of time in MATLAB, with my focus on signal processing and data analysis.

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Solved

Project Euler: Problem 10, Sum of Primes
The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below the input, N. Thank you <http:/...

3 days ago

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Project Euler: Problem 8, Find largest product in a large string of numbers
Find the greatest product of five consecutive digits in an n-digit number. 73167176531330624919225119674426574742355349194934...

3 days ago

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Project Euler: Problem 7, Nth prime
By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13. What is the Nth prime nu...

3 days ago

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Project Euler: Problem 6, Natural numbers, squares and sums.
The sum of the squares of the first ten natural numbers is, 1^2 + 2^2 + ... + 10^2 = 385 The square of the sum of the first ...

3 days ago

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Project Euler: Problem 5, Smallest multiple
2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder. What is the smalle...

3 days ago

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Project Euler: Problem 4, Palindromic numbers
A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 ...

13 days ago

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Project Euler: Problem 3, Largest prime factor
The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number being input, input might be ui...

13 days ago

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Project Euler: Problem 2, Sum of even Fibonacci
Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 te...

13 days ago

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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...

13 days ago

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How long is the longest prime diagonal?
Stanislaw Ulam once observed that if the counting numbers are <http://en.wikipedia.org/wiki/Ulam_spiral arranged in a spiral>, t...

13 days ago

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Calculate the area of a triangle between three points
Calculate the area of a triangle between three points: P1(X1,Y1) P2(X2,Y2) P3(X3,Y3) these three points are the vert...

13 days ago

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Is the Point in a Triangle?
Check whether a point or multiple points is/are in a triangle with three corners Points = [x, y]; Triangle = [x1, y1; x...

13 days ago

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Right Triangle Side Lengths (Inspired by Project Euler Problem 39)
If _p_ is the perimeter of a right angle triangle with integral length sides, { _a_, _b_, _c_ }, there are exactly three solutio...

13 days ago

Question

Can I use arrows to move Data Tips on scatter plots?
I know that when using the plot function with data tips you can use the arrow keys to move the data tip through the data set. Is...

18 days ago | 2 answers | 0

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answers

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Find the sides of an isosceles triangle when given its area and height from its base to apex
Find the sides of an isosceles triangle when given its area and the height from its base to apex. For example, with A=12 and ...

19 days ago

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Can we make a triangle?
Given three positive number, check whether a triangle can be made with these sides length or not. remember that in a triangle su...

19 days ago

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Height of a right-angled triangle
Given numbers a, b and c, find the height of the right angled triangle with sides a and b and hypotenuse c, for the base c. If a...

19 days ago

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Find my daddy long leg (No 's')
Given the ratio of the two legs (longer / shorter), and the hypotenuse length, find the value of the bigger leg.

19 days ago

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Natural numbers in string form
Create a cell array of strings containing the first n natural numbers. _Slightly_ harder than it seems like it should be. Ex...

20 days ago

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Fix the last element of a cell array
Note: this is lifted directly from <http://www.mathworks.com/matlabcentral/answers/82825-puzzler-for-a-monday Puzzler for a Mond...

20 days ago

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String Array Basics, Part 1: Convert Cell Array to String Array; No Missing Values
<http://www.mathworks.com/help/matlab/characters-and-strings.html String array> and cell array are two types of containers for s...

20 days ago

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Cell Counting: How Many Draws?
You are given a cell array containing information about a number of soccer games. Each cell contains one of the following: * ...

20 days ago

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Remove element(s) from cell array
You can easily remove an element (or a column in any dimension) from a normal matrix, but assigning that value (or range) empty....

20 days ago

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Convert a Cell Array into an Array
Given a square cell array: x = {'01', '56'; '234', '789'}; return a single character array: y = '0123456789'

20 days ago

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Split a string into chunks of specified length
Given a string and a vector of integers, break the string into chunks whose lengths are given by the elements of the vector. Ex...

20 days ago

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Convert a numerical matrix into a cell array of strings
Given a numerical matrix, output a *cell array of string*. For example: if input = 1:3 output is {'1','2','3'} whic...

20 days ago

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Create a cell array out of a struct
Create a cell array out of a (single) struct with the fieldname in the first column and the value in the second column: in: ...

20 days ago

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There are 10 types of people in the world
Those who know binary, and those who don't. The number 2015 is a palindrome in binary (11111011111 to be exact) Given a year...

1 month ago

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Converting binary to decimals
Convert binary to decimals. Example: 010111 = 23. 110000 = 48.

1 month ago

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Binary code (array)
Write a function which calculates the binary code of a number 'n' and gives the result as an array(vector). Example: Inpu...

1 month ago