# David Fletcher

### De Montfort University

Prior roles - technician (pharmaceutical chemistry, pharmacognosy and electron microscopy). Currently working as a senior technician in pharmaceutical technology.

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**Content Feed**

Solved

Create an n-by-n null matrix and fill with ones certain positions

The positions will be indicated by a z-by-2 matrix. Each row in this z-by-2 matrix will have the row and column in which a 1 has...

10 months ago

Solved

Calculate a Damped Sinusoid

The equation of a damped sinusoid can be written as |y = A.ⅇ^(-λt)*cos(2πft)| where |A|, |λ|, and |f| ...

10 months ago

Solved

Solve a System of Linear Equations

*Example*: If a system of linear equations in _x₁_ and _x₂_ is: 2 _x₁_ + _x₂_ = 2 _x₁...

10 months ago

Solved

Magic is simple (for beginners)

Determine for a magic square of order n, the magic sum m. For example m=15 for a magic square of order 3.

10 months ago

Solved

Make a random, non-repeating vector.

This is a basic MATLAB operation. It is for instructional purposes. --- If you want to get a random permutation of integer...

10 months ago

Solved

Number of 1s in a binary string

Find the number of 1s in the given binary string. Example. If the input string is '1100101', the output is 4. If the input stri...

10 months ago

Solved

Return the first and last characters of a character array

Return the first and last character of a string, concatenated together. If there is only one character in the string, the functi...

10 months ago

Solved

Getting the indices from a vector

This is a basic MATLAB operation. It is for instructional purposes. --- You may already know how to <http://www.mathworks....

10 months ago

Solved

Check if number exists in vector

Return 1 if number _a_ exists in vector _b_ otherwise return 0. a = 3; b = [1,2,4]; Returns 0. a = 3; b = [1,...

10 months ago

Solved

Generate a vector like 1,2,2,3,3,3,4,4,4,4

Generate a vector like 1,2,2,3,3,3,4,4,4,4 So if n = 3, then return [1 2 2 3 3 3] And if n = 5, then return [1 2 2...

10 months ago

Solved

Maximum value in a matrix

Find the maximum value in the given matrix. For example, if A = [1 2 3; 4 7 8; 0 9 1]; then the answer is 9.

10 months ago

Solved

Find the Oldest Person in a Room

Given two input vectors: * |name| - user last names * |age| - corresponding age of the person Return the name of the ol...

10 months ago

Solved

Convert from Fahrenheit to Celsius

Given an input vector |F| containing temperature values in Fahrenheit, return an output vector |C| that contains the values in C...

10 months ago

Solved

Calculate Amount of Cake Frosting

Given two input variables |r| and |h|, which stand for the radius and height of a cake, calculate the surface area of the cake y...

10 months ago

Solved

Roll the Dice!

*Description* Return two random integers between 1 and 6, inclusive, to simulate rolling 2 dice. *Example* [x1,x2] =...

4 years ago

Solved

Finding Perfect Squares

Given a vector of numbers, return true if one of the numbers is a square of one of the other numbers. Otherwise return false. E...

4 years ago

Solved

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 = ...

4 years ago

Solved

Too mean-spirited

Find the mean of each consecutive pair of numbers in the input row vector. For example, x=[1 2 3] ----> y = [1.5 2.5] x=[1...

4 years ago

Solved

Bottles of beer

Given an input number representing the number of bottles of beer on the wall, output how many are left if you take one down and ...

4 years ago

Solved

How to find the position of an element in a vector without using the find function

Write a function posX=findPosition(x,y) where x is a vector and y is the number that you are searching for. Examples: fin...

4 years ago

Solved

Find the longest sequence of 1's in a binary sequence.

Given a string such as s = '011110010000000100010111' find the length of the longest string of consecutive 1's. In this examp...

4 years ago

Solved

Which values occur exactly three times?

Return a list of all values (sorted smallest to largest) that appear exactly three times in the input vector x. So if x = [1 2...

4 years ago

Solved

Sort a list of complex numbers based on far they are from the origin.

Given a list of complex numbers z, return a list zSorted such that the numbers that are farthest from the origin (0+0i) appear f...

4 years ago

Solved

Remove all the consonants

Remove all the consonants in the given phrase. Example: Input s1 = 'Jack and Jill went up the hill'; Output s2 is 'a ...

4 years ago

Solved

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...

4 years ago

Solved

Nearest Numbers

Given a row vector of numbers, find the indices of the two nearest numbers. Examples: [index1 index2] = nearestNumbers([2 5 3...

4 years ago

Solved

Balanced number

Given a positive integer find whether it is a balanced number. For a balanced number the sum of first half of digits is equal to...

4 years ago

Solved

Matrix with different incremental runs

Given a vector of positive integers a = [ 3 2 4 ]; create the matrix where the *i* th column contains the vector *1:a(i)...

4 years ago

Solved

Rotate input square matrix 90 degrees CCW without rot90

Rotate input matrix (which will be square) 90 degrees counter-clockwise without using rot90,flipud,fliplr, or flipdim (or eval)....

4 years ago