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# Paul Johnson

##### Last seen: 2 mois ago
41 total contributions since 2020

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Problem

Find the point of intersection of tangents.
Given two points on a conic, find the point of intersection of the corresponding tangents. The conic is given in Cartesian co...

11 mois ago | 0 | 3 solvers

Problem

Find the shortest distance between a point and a straight line.
Given the Cartesian coordinates of three points A, B and C (in a flat Euclidean space), find the shortest distance between the ...

11 mois ago | 1 | 7 solvers

Solved

Kepler's Equation
Solve <http://en.wikipedia.org/wiki/Kepler's_equation Kepler's Equation>. Note that the solution is rounded down to 5 decima...

12 mois ago

Solved

Calculate the height of an object dropped from the sky
Assume that an object is dropped from 1000 meters above the surface of the earth at time t=0. The object is dropped such that t...

12 mois ago

Question

Problem editing a draft Cody problem.
Hello, I have saved some draft Cody problems, but I am unable to edit these drafts. A message appears to the effect that "some...

12 mois ago | 0 answers | 0

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Solved

Find the numeric mean of the prime numbers in a matrix.
There will always be at least one prime in the matrix. Example: Input in = [ 8 3 5 9 ] Output out is 4...

12 mois ago

Solved

Indexed Probability Table
This question was inspired by a Stack Overflow question forwarded to me by Matt Simoneau. Given a vector x, make an indexed pro...

12 mois ago

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...

12 mois ago

Solved

Bullseye Matrix
Given n (always odd), return output a that has concentric rings of the numbers 1 through (n+1)/2 around the center point. Exampl...

environ un an ago

Solved

Find all elements less than 0 or greater than 10 and replace them with NaN
Given an input vector x, find all elements of x less than 0 or greater than 10 and replace them with NaN. Example: Input ...

environ un an ago

Solved

Knight's Tour Checker
Given a matrix a, determine whether or not a legal <http://en.wikipedia.org/wiki/Knight's_tour knight's tour> is present. The kn...

environ un an ago

Solved

Given a and b, return the sum a+b in c.

environ un an ago

Solved

Make a checkerboard matrix
Given an integer n, make an n-by-n matrix made up of alternating ones and zeros as shown below. The a(1,1) should be 1. Examp...

environ un an ago

Solved

Who Has the Most Change?
You have a matrix for which each row is a person and the columns represent the number of quarters, nickels, dimes, and pennies t...

environ un an ago

Solved

Back and Forth Rows
Given a number n, create an n-by-n matrix in which the integers from 1 to n^2 wind back and forth along the rows as shown in the...

environ un an ago

Solved

Is my wife right?
Regardless of input, output the string 'yes'.

environ un an ago

Solved

Pizza!
Given a circular pizza with radius _z_ and thickness _a_, return the pizza's volume. [ _z_ is first input argument.] Non-scor...

environ un an ago

Solved

Determine whether a vector is monotonically increasing
Return true if the elements of the input vector increase monotonically (i.e. each element is larger than the previous). Return f...

environ un an ago

Solved

Weighted average
Given two lists of numbers, determine the weighted average. Example [1 2 3] and [10 15 20] should result in 33.333...

environ un an ago

Solved

Swap the first and last columns
Flip the outermost columns of matrix A, so that the first column becomes the last and the last column becomes the first. All oth...

environ un an ago

Solved

Sum all integers from 1 to 2^n
Given the number x, y must be the summation of all integers from 1 to 2^x. For instance if x=2 then y must be 1+2+3+4=10.

environ un an ago

Solved

Inner product of two vectors
Find the inner product of two vectors.

environ un an ago

Solved

Get the length of a given vector
Given a vector x, the output y should equal the length of x.

environ un an ago

Solved

Triangle Numbers
Triangle numbers are the sums of successive integers. So 6 is a triangle number because 6 = 1 + 2 + 3 which can be displa...

environ un an ago

Solved

Determine if input is odd
Given the input n, return true if n is odd or false if n is even.

environ un an ago

Solved

Back to basics 6 - Column Vector
Covering some basic topics I haven't seen elsewhere on Cody. Given an input vector, output true or false whether it is a colu...

environ un an ago

Solved

Sum the numbers on the main diagonal
Sum the numbers on the main diagonal of an n-by-n matrix. For input: A = [1 2 4 3 6 2 2 4 7]...

environ un an ago

Solved

Area of a circle
Find the value for area of the circle if diameter is given

environ un an ago

Solved

Vectors counting by 2
Create a vector numbers from 7 to 15 in increments of 2

environ un an ago

Solved

find the maximum element of the matrix
for e.g x = [1 2; 3 4] y = 4

environ un an ago