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# PetronasAMG

Last seen: 2 months ago Active since 2017

Engineering student who needs a lot of help with matlab!

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Question

How to use spline interpolation to find intersection point of two lines.
Hi, Just new to matlab and still trying to understand spline interpolation. Although we can eye ball the interspection point, ho...

3 months ago | 2 answers | 0

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Question

Integrating a 2nd order ODE
I am given an equation, d^2y/dx^2 + q(x) = 0 x ranges from 0 to 1 and y(0) = 1 and y(L) = 1.5 where L = 1 and q(x) = 2*cos...

3 months ago | 1 answer | 0

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Question

how to linear interpolate using a for loop
say I have a y = x^2 -2; I want to find out which point of x it crosses y = 0 by linear interpolating. But by showing when the ...

4 months ago | 1 answer | 0

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Question

how to get eigenvalues and plot it
say time is varying from 1< t < 10 I also set the element of matrix a1 = t/1, a2 = t +2 / 3 ,a3 = t/2 ,a4 = t+5 then i set u...

4 months ago | 1 answer | 0

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Question

error getting eigenvalues varying with time
xcg = 0.15; rea = 0.5; xe = 0.35; cla=2*pi ; m= 5*pi; a0 = 0; wr = (1/2); mu = 1+(3*a0^2); U = 0:0.01:1; a1 = ((mu*((U.*c...

4 months ago | 1 answer | 0

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Question

Eigenvalue and Eigenvector extracting
so I have a time array say, 0< t < 10 My elements of matrix are function that will depend on variable t. Say, a11 = (t^2)/2 ,a...

4 months ago | 1 answer | 0

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Question

How to get eigenvalues with varying coefficient
I have t varing from 0 < t < 5 and x1 = (1+t)/2, x2 = (t^2)/4 and x4 = (1+2t)/6 so i did linspace(0,5,5) A = [x1 x2; 0 x4]; ...

4 months ago | 1 answer | 0

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Question

how to interpolate the data over uniform time grid
Since numerical solution obtained from ode45 is a non uniform in time, I need to obtain the frequency power spectrim of the solu...

4 months ago | 0 answers | 0

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Question

How to create a Frequency Spectrum plot from nonlinear equations
given three nonlinear equations dx1/dt = 3(x1+x2) dx2/dt = x1 - (1/6)x2 dx3/dt = (1/7) + (x1 -3.25)*x3 and their correspodin...

4 months ago | 0 answers | 0

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Question

How to computer a frequency spectrum and find its largest spectral energy
I am given set of equation I am suppose to plot x1 x2 and x3 as a 3d dimensional phase, but direction wants me to omit any pos...

4 months ago | 1 answer | 0

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Question

Using ODE45 for first order diff equation with three different variables
So, I am trying to use ODE45, say dx/dt = (0.1*x)+(0.25*y)-(9.8*z) I am trying to graph the behavior of x,y and z from time (0...

4 months ago | 1 answer | 0

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Question

pulling our elements from a matrix using for loop
if matrix A = [1 3 4 2 17 6 4 5 2] what is a matrix command that i can use it to pull first 6 elements?

4 years ago | 1 answer | 0

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Question

comparing cells in excel then calculate for the sum
So I will try my best to explain this. So I need to find the sum of weight given chart, <</matlabcentral/answers/uploaded_f...

4 years ago | 1 answer | 0

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Question

while loop error with conditional statment
i %ignore this i code starts from below interval = 1.2 x_int = 0:intereval:c i=1 while x_int(i) <= c ya(i) = ((5...

4 years ago | 1 answer | 0

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Question

for example, A = [1 2 3 4 5] B = [0 0 0 0 0 6 7 8 9 10] and i need C = [1 2 3 4 5 6 7 8 9 10] is there a way to make...

4 years ago | 1 answer | 0

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Question

Conversion to logical from sym is not possible.
This is what I have syms x; ...

4 years ago | 1 answer | 0

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Question

so this is what I have.. <</matlabcentral/answers/uploaded_files/103530/Capture1.PNG>> but i need to make my graph look li...

4 years ago | 1 answer | 0

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Question

graph comes out all rotated
so this is what i have posdegreeline = refline(tand(-45),0); negdegreeline = refline(tand(45),0); posdefreeline.Color...

4 years ago | 0 answers | 0

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Question

unheard of ptitle command.. what is this???
so i am pulling out data from excel files as my input and export all my calculated data from matlab to excel output. So far ever...

4 years ago | 2 answers | 0

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Question

index exceeds matrix demension
figure(1) hold on; plot(1.25,1.25,'ro'); i=1; while i <= 20 plot([xi(i),xj(i)],[yi(i),yj(i)],'b'); ...

4 years ago | 1 answer | 0

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Question

how to shift origin or graph without changing the data value.
Let's say you have a (x,y) = (1,1) however is there a possible way to show another quadrant of the graph? Every time i try to se...

4 years ago | 1 answer | 0

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Question

Distance formula using while loop
so i given a data file, I was able to call in these values into Matlab input <</matlabcentral/answers/uploaded_files/103383/S...

4 years ago | 2 answers | 0

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Question

How to rescale x- axis?
so when i plot my function, i get a wide graph. <</matlabcentral/answers/uploaded_files/101612/Screen%20Shot%202018-01-17%20a...

4 years ago | 1 answer | 0

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Question

Data must be a single matrix Y or a list of pairs X,Y. Need help on plotting 3D graph!
array= Tmax/n; %This expends the data points n = 2000 and Tmax = 20 t = 0:array:Tmax; ...

4 years ago | 1 answer | 0