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Maximize answer of second order Polynomial inequality
Hi Luuk It makes more sense to find the boundaries of the inequality: syms x eqn1 = 0.99*x^2-99==0; x_num = solve(eqn1, x) ...

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Distribute a sum using binomial distribution
Hi Vorticella, In the code you are using, the two numbers are chosen independently and usually don't add up to be the row sum. ...

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How to avoid introducing abs( ) when simplifying expressions using the symbolic toolbox ?
Hello Prajwal, norm_v = abs(xdot)/abs(cos(x)) so it does fundamentally depend on abs. Since norm_v is being divided into quan...

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Recurrence relation for polynomial indices
Hello Jaime, Suppose you want the results up to a polynomial of degree p. The following code creates a (p+1)x(p+1) matrix c of...

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How can I represent the sparse mass, damping and stiffness matrices in state space?
HI 'M', Suppose you have n positions and n corresponding velocities. Let the state space (column) vector be in the order y = ...

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Adding matrices (to assemble global stiffness matrix)
Hi Ryan, here is an example. In the code below, a and b are the indices of the 4x4 submatrix of K that each stiffness submatri...

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Wrong answer being given when adding whole numbers
Hello Matthew, this is happening because the image uses uint8 values (unsigned integer 8 bit), with a range of 0 to 2^8 -1 = 25...

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How to calculate energy of the signal at a specific frequency after applying FFT
Hello Daniel, To get the desired result you have to be careful about the number of points, so that an exact number of oscillati...

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How to multiply each column in the matrix by different scientific notation values that should be imported from a txt file?
HI Gabrielle, MODIFIED Looks like you have constructing the 128x256 matrix of values covered. The code below converts S{1} to...

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Using numerical methods to plot solution to first-order nonlinear differential equation
Hello Aleem, You are saying that the analytical solution is not relevant because it involves complex numbers, but that's not th...

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MATLAB determine if matrices are invertible or not
Hi SS P+Q ans = 9 9 2 13 0 0 3 4 -3 -3 6 1 1 1 2 6 det(P+Q) ans = ...

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Solve matrix series equation
Hi Ramesh, This is an overdetermined system, but if you define x as a 2x7 matrix of 2d coordinate values and X as a correspondi...

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interpreting frequency vs phase plot in fft
Hello JL, Since sin(2*pi*f*t) = ( e^(2*pi*i*f*t)-e^(-2*pi*i*f*t) )/(2i), (1) the sine signal has both positive and ...

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Why does the cscvn function of matlab have 4*2*(n-1) coefficients?
Hello Ashkan, factor of (n-1) because n points --> (n-1) intervals, and the polynomials are defined on the intervals factor o...

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Solving a transcendental equation
Hi Kubilay, Finding an algebraic solution for this equation in terms of lambda is not going to happen. But a numerical solutio...

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How to use Poisson distribution?
Hi Jaya, You appear to be saying that you can't use a loop to increment through event times. For example, though, just before ...

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I want to treat w as a constant
Hello HJ, try replacing the first line with syms y(x) w real in which case the result is ySol(x) = (exp(-x)*(sin(w*x) + w*c...

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Setting a 3rd vector with specific angles to 2 other vectors
Hi Huseyin, The method you are using gets you into an iterative process of successive rotations about the x and z axis that eve...

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ODE system with 2 degrees of freedom
Hi Nader, you only need four variables, theta1, theta1dot, theta2, theta2dot (not six). Try function dydt = ODEsystem(t,y) k...

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How to prove the positivity if this function?
Hi Andrea, What might constitute a proof using Matlab is a good question. If the answer to isAlways(y>=0) had come out as 1, w...

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fixing of random number
Hi Irani, If I understand your question correctly, rng(1) Y = randi(10) rng('shuffle') node = randi(20) gives the same val...

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how to find the angle subtended from origin to the poles in complex plane?
Hello Muhammed, it's as easy as angle(65+65j) angle(65-65j) with each angle in radians subtended from the x axis, -pi < angl...

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Matlab and Fortran Precision Issue
Hello SA It's the constants. First of all for simplicity I commented out everythng not concerned with calculation of ORIGINAL_...

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How do you inverse fourier transform 2D data only in one direction?
Hi Gabrielle, I'm not exactly sure what is meant by 'in the x direction' but it sounds like dimension 2. Anyway, ifft(Y,[],2)...

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Principal Component Analysis: difference between V matrix from SVD decomposition and coef from pca?
Hello Jessica, The set of column vectors that define V in svd, or define coeff in pca, can differ from each other by a factor o...

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extract roll pitch yaw rotation angles from 3D transform
Hello "AT" fwiw, here is a version of finding three rotation angles th1,th2,th3 from a 3d rotation matrix defined below. Ang...

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my question is what is wrong with my code, the results should be in the first picture not the second.
Hi jana, the problem is that the if statements if mod(row,2)==0 && mod(col,2) ==1 && col>=3 % (b) and i...

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My solver is giving extremely large numbers for a straight forward system of linear equations, what's wrong?
Hi John, What the solver is trying to tell you is that a solution does not exist for this problem, or more correctly it exists ...

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Finding Argument of Bessel Function (1st Kind) to Return Known Solution
Hello 1:5, syms r ex = 5; R = 160; F = besselj(0,(2.405*r)/(R + ex)); Ratio = 0.3005; q = F == Ratio; vpasolve(q,r,[0 ...

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Multiplication of sparse matrix and a normal matrix
Hi Amit, sum(S)' where the result is still sparse, or full(sum(S)') if you want a regular vector at that point.

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