# Giorgos Papakonstantinou

### NTUA

I have only made this code longer because I have not had the time to make it shorter

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Solved

Summing digits

Given n, find the sum of the digits that make up 2^n. Example: Input n = 7 Output b = 11 since 2^7 = 128, and 1 + ...

6 years ago

Solved

Binary numbers

Given a positive, scalar integer n, create a (2^n)-by-n double-precision matrix containing the binary numbers from 0 through 2^n...

6 years 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...

6 years ago

Solved

What's Your BMI?

Find the body mass index. For reference, please refer to Wikipedia here: <http://en.wikipedia.org/wiki/Body_mass_index body ...

6 years ago

Solved

Return the 3n+1 sequence for n

A Collatz sequence is the sequence where, for a given number n, the next number in the sequence is either n/2 if the number is e...

6 years ago

Solved

Use R2016b Text Manipulations to Fix These Addresses (Part 1)

We have a series of addresses like the following which we'd like to reformat. Can you remove the latitude and longitude from the...

6 years ago

Question

Determine transfer function from block diagram

I am having trouble to define in matlab the transfer function of the following block diagram. <</matlabcentral/answers/upload...

7 years ago | 1 answer | 0

### 1

answerHow to select a cell from an array when this array is made of functions of a parameter?

You can do A{2} or A{1,2}

7 years ago | 0

I don't get it... Help plotting this on MATLAB?

Annalise I will try to demonstrate how you may plot a piecewise function. In a similar manner you may plot yours. Lets assume...

8 years ago | 0

| accepted

Character input error message !!

If the |string| you get |from handles.m| is a _char_ class then |str2num| will produce an empty matrix. >> str2num('hello...

8 years ago | 0

how can i change cell array to matrix

You can do the following to find which values are >=-15 : dat= {'A' [12] [-20] [-75] [66] 'B' [9] [-10] [-50] [55] 'C' [15]...

8 years ago | 0

Ceate a vector of state space variable like A=[x(1), x(2), x(3),.....x(21)]

Hallo Ismaeel. There is no need to use loop to do that. Check the |<http://nl.mathworks.com/help/matlab/ref/colon.html colon>| u...

8 years ago | 0

Reverse order in column;flipud ain't giving me that.

Try to put outside the first loop: K = fliplr(I);

8 years ago | 1

| accepted

create a function that is the derivate of a f=@(t) function

Maybe this: fa = @(x)x^5-0.4475*x.^4-3.1*x.^3+3.085*x.^2-0.962*x+0.0943 g = sym(fa); dg = diff(g); df = matlabFu...

8 years ago | 0

| accepted

Conversion of a matrix into multiple column vectors

x1 = A(:,1).'; x2 = A(:,2).';

8 years ago | 2

Estimate length with out NaN's

If |x| is your vector. YourLength = length(x) - sum(isnan(x))

8 years ago | 1

Choosing specific area of points from xscale in plot

Hallo Tom. One way is to use brush/Select Data tool: <</matlabcentral/answers/uploaded_files/26924/Capture.png>> (ap...

8 years ago | 0

I would like to define a function that allows me to enter a symbolic expression in terms of x, raise that expression to the "n"th degree, then plot that expression from x=[-5,5]

Justin you have to define outside your function what is |x|. This is the reason why Matlab complains about |x|. It does not know...

8 years ago | 0

How to rotate xaxis labels (bar graph)

Read: <http://nl.mathworks.com/matlabcentral/answers/103026-how-can-i-rotate-my-x-axis-tick-labels-and-place-an-x-label-on-my-pl...

8 years ago | 0

| accepted

How can i read multiples files from a directory?

Assuming you want to open a few files. Create a cell|filenames|. Then the loop would be like this> filenames = {'file1....

8 years ago | 0

How to put script on pause instead of quitting when encountering error

Ekaterina, as far as I know you, could enclose the part of the code, which tries to establish a connection within a <http://nl.m...

8 years ago | 1

How to put radiobutton in GUI to cycle if?

If we assume the radiobutton handle variable name is |radio| then your |if| statement inside the |pushbutton1_Callback| should b...

8 years ago | 0

| accepted

Importing Data outputted by FreeFem++

u = [1 2 3 4 5; 6 7 8 9 10; 11 12 13 14 15]; reshape(permute(u,[2 1]), [], 1) or more compact: u ...

8 years ago | 0

| accepted

Does changing the axes turn tick marks off?

If you want to remove the ticks from both *x axis* and *y axis* , do this: set(gca,'Xtick',[], 'Ytick', [])

8 years ago | 0

Plotting (1-2*x)*log((1-x)/x)

The problem occurs inside the *log* parenthesis. The syntax that you have used tells Matlab to solve the equation: x = B/A ...

8 years ago | 1

Multiplying even and odd columns separately?

Here is one way: A =rand(100, 50); idx = mod(1:size(A,2), 2) ==1; % logical indexing of the odd numbers the...

8 years ago | 1

Creating a shape with varying arcs?

If I understood correctly you mean a spiral. Here's one way then: turns=5; theta = 0:pi/180:2*pi*turns; r = 2*o...

8 years ago | 0

Solving a formula in Matlab

x = input('Enter the value of x: '); % request user input y = input('Enter the value of y: '); S = input('Enter the ...

8 years ago | 0

| accepted

uiparent in Matlab 2013b

These are value/pair arguments. That means you have to write explicitly: hsp = uipanel('Parent', hp)

8 years ago | 0

How do I use the function "uicontrol" ?

The minimum example I can give you is: sld = uicontrol('Style', 'slider',... 'Min',1,'Max',50,'Value',41,... ...

8 years ago | 0

| accepted