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# Aleem Andrew

Last seen: 3 months ago Active since 2020

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Solving algebraic equations without using symbolic variables
How do you solve an algebraic equation like x+y=2 for x without using symbolic variables - for example by defining a function ha...

3 months ago | 1 answer | 0

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Reading an Excel table with both numbers and text
I read an Excel table using the readtable function. I wanted to refer to specific values, whether text or numbers, but when I tr...

6 months ago | 1 answer | 0

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Updating values in a matrix when corresponding variable values are updated
In the code below, when a, a variable in matrix w, is updated the matrix does not automatically update. Is there a way to update...

6 months ago | 1 answer | 0

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Aligning numbers with text in a table
In the code below, the numbers all occupy 13 characters of space. How do you align the words and numbers so each word also occup...

6 months ago | 1 answer | 0

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Keeping track of order of rows when sorting a matrix
I am trying to sort the matrix B below and also keep track of the order in which rows get swapped. B = [100000001 0100001...

7 months ago | 1 answer | 0

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Input argument for ode45 function type error
I am trying to modify the following code. tspan = [0 10]; x0 = 0; [t,x] = ode45(@(t,x) (-4.76e+1*x^2 + 5.69e-9*x + 7.98e-2)/...

7 months ago | 1 answer | 0

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Simplifying output in Matlab
If you get an expression like this as output syms x fx = -(1.0*(1.82e+39*x^2 + 1.81e+32*x - 3.04e+39))/(6.35e+41*x + 4.27e+3...

7 months ago | 1 answer | 0

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Using numerical methods to plot solution to first-order nonlinear differential equation
I have a question about plotting x(t), the solution to the following differential equation knowing that dx/dt equals the express...

7 months ago | 1 answer | 0

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Finding roots of symbolic expression
You cannot directly use the roots function to find the roots of a symbolic expression. syms x fx = x^2 + 2*x + 1 How do you ...

7 months ago | 1 answer | 0

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Merging row elements into single numbers
If you have the 3*3 matrix C = [3 4 5 6 7 9 1 5 8] and you want to change it to the 3*1 matrix C = [345 679...

7 months ago | 1 answer | 0

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Question

Merging rows of a matrix into a number
If you have the 3*1 matrix C = [345 679 158] and you want to change it to the 3*3 matrix (or vice versa) C = [3 4...

7 months ago | 2 answers | 0

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Output of Deconv function Matlab
When you type the command deconv([1 -3 -52],[1 -4]) the answer is 1 1 which I did not expect since (x+1)(x-4) is not (x^2-3x...

1 year ago | 1 answer | 0

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Question

Inconsistency of angle function in finding angle of vectors
Typing the command angle(1+i) yields an angle of 45 degrees, but typing angle(-1-2i) yields -2.0344. Why is the angle being meas...

1 year ago | 2 answers | 0

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Plotting responses other than step responses to transfer function
I am trying to plot the response of a transfer function to an arbitrary input. The step response can be plotted as shown below. ...

1 year ago | 1 answer | 0

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Find range of values of independent variable so the dependent variable is in a certain range
Given a function for example f(x) = x^3+x^5 is there a way you can determine all values of x such that the absolute value of f(x...

1 year ago | 1 answer | 0

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Finding the ramp response to a transfer function
If T is the transfer function defined below, how do you find the ramp response? G = tf(poly([-2 -3]),poly([0 -1])); T=feedback(...

1 year ago | 1 answer | 0

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More accurate alternative to rlocfind to analyze root locus in control systems engineering
To find the gain at the point where the root locus intersects a line of constant damping ratio, the rlocfind function can be use...

1 year ago | 0 answers | 1

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Using deconv to divide vectors if the numerator has a smaller degree than the denominator
When using deconv to divide two vectors the output is 0 if the numerator has a smaller degree than the denominator. Can you get ...

1 year ago | 1 answer | 0

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Dividing two vectors of different sizes
If you have two vectors a = [1 2 1]; b = [1 1] that represent polynomials can you divide a by b to get [1 1] as the answer, sinc...

1 year ago | 1 answer | 0

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Convert a structure array to a list
I am trying to convert a structure array into a list rather than a cell to be able to perform operations such as finding the inv...

1 year ago | 1 answer | 0

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Unable to convert expression containing symbolic variables into double array error
I am trying to define a vector xdd in terms of another vector x but when I define elements of the vector xdd in terms of the cor...

1 year ago | 1 answer | 0

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Finding inverse Laplace when the inverse Laplace function is a piecewise function
I wrote the following Matlab program to find x in the time domain. syms y(t) m k x c w F s eqn = s^2*x-s+2*s*x-2+2*x == exp...

1 year ago | 1 answer | 0

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Displaying a group of vectors on separate lines
I am trying to display a number of vectors in separate lines. How can you create a matrix with each its rows equal to one a grou...

1 year ago | 1 answer | 0

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Solve for a variable in terms of specific other variables
The derivative of eq1 below is diff(x(t), t) == diff(y(t), t). I am trying to use the solve function to solve for diff(y(t)) and...

1 year ago | 1 answer | 0

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Solving differential equations and specifying initial conditions
Given an equation, can you solve for the derivatives of certain quantities in terms of the other variables? For example in the f...

1 year ago | 0 answers | 0

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Check for missing argument or incorrect argument data type in call to function 'solve'. error
I am trying to solve for a variable using the solve command. I know I can do so symbollically, but I want to first intiailize th...

1 year ago | 1 answer | 0

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Finding a closed form solution of nonlinear differential equation
Can you find an expression for x, which is a function of t, given that sin(x*t) + t^2*cos(3*t^2)+x''(t) = 5x (x''(t) is the seco...

1 year ago | 1 answer | 0

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Plotting path traced by a point in an animation
The following code creates an animation of a four bar linkage. Can someone explain how you can modify the code to plot the path ...

1 year ago | 1 answer | 0

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Finding the magnitude of an expression
Supposing that x can be expressed as a function of t as follows how can its magnitude be found using Matlab? For example, is the...

1 year ago | 1 answer | 0