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Questions tagged [simplifying-expressions]

Questions on manipulating complicated expressions and making them look simpler using Simplify, FullSimplify and Reduce.

2
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0answers
18 views

Finding common terms in an expression to simplify further?

When I write a manuscript which has two columns, usually it's hard for me to fit a big expression into one line. I usually simplify the expression further by manually finding some common terms (...
2
votes
2answers
53 views

Keeping specific terms in Mathematica output

After solving an equation I came up with a complicated expression, is it possible to only keep some specific terms of an expression ? As an example, if the expression is: How can I keep only those ...
0
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0answers
33 views

FindRoot for a transcendental function (PolyLog)

I am trying to solve an equation involving polylog using FindRoot, I am not sure how to give the initial guess as I want to solve the equation for a variety of parameters. Here is my code: ...
3
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0answers
16 views

Kernel crash when simplifying piecewise function

So the kernel appears to just die whenever you try to simplify a piecewise function containing "Nothing". For example: this appears to kill the kernel $$\text{Simplify@}\begin{array}{cc} \Bigl[\...
0
votes
1answer
100 views

How to simplify $(x^{1/y})^y$?

I would like Mathematica to be able to simplify the expression $\left(x^{1/y}\right)^y$ to $x$. However, running Simplify[(x^(1/y))^y] does not accomplish the ...
0
votes
0answers
28 views

Issue with simplifying symbolic expression(s). Forcing a certain simplification [closed]

I have an expression, which Mathematica doesn't want to simplify any further: (1 + (1 + Subscript[x, 2])^2/( Subscript[x, 1] Subscript[x, 3]))/Subscript[x, 2] I ...
1
vote
0answers
68 views

How can I get Mathematica to recognize that $ab^* + ba^* = 2\Re(ab^*)$?

Mathematica understands that $z + z^* = 2\Re(z)$, FullSimply[z + Conjugate[z]] (* output: 2 Re[z] *) However, Mathematica does not simplify the expression ...
1
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0answers
28 views

Make a function invariant under a permutation of the arguments

The output of my current notebook contains expressions that look as follows (V[{k,q},{s,t}] + V[{-k, -q}, {t,s}]) In my specific application these two functions ...
2
votes
1answer
92 views

Seems like OptimizeExpression is getting worse over time

I've been using the OptimizeExpression function again recently, and cleaning up the results by hand. Its results have been unbelievably sub-optimal in my recent ...
1
vote
1answer
38 views

Issues with negative sign in front of rules for Logarithm simplification

I declare a very simple rule. rule = -x_*Log[a_] :> x*Log[1/a] Now I give two expressions, -x Log[d] /. rule which ...
1
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0answers
44 views

How to simplify Log expressions using rules

I have the following expression, ...
2
votes
3answers
78 views

Checking if two expressions are related

Is it possible in mathematica to check if two expressions may be able to be written in terms of the other? The expressions I had in mind were of the form $$\alpha = \frac{1-x}{1-y}\,\,\,\,,\,\,\ \beta ...
1
vote
1answer
56 views

Finding Coefficients of the Product of Sums

Is there any way to get Mathematica to find the coefficients of the product of sums? As an example (the problem I am trying to solve): Coefficients for a Taylor expansion of $e^{z^2}$ centered around $...
0
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0answers
29 views

Too many intermediate equations

I try to explain what skew lines are, and how to present them, little by little, calculate different intermediate values, this code works, but it is a frankenstein code, even with comments it's hard ...
6
votes
2answers
76 views

Get the intermediate steps of FullSimplify

I have this expression: Log[i] > (i Log[i])/n + Log[n - i] - (i Log[n - i])/n And I attempt to simplify it and get this: ...
0
votes
1answer
37 views

Simplifying an expression involving a matrix and functions of it

I have implemented the following two matrices in Mathematica in order to compute s, but I don't know how I can further simplify the resulting expressions, e.g., ...
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2answers
50 views
0
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0answers
42 views

Transcendental equation analytical solving

I want to solve a transcendental equation analytically, the equation basically is ...
1
vote
0answers
51 views

Possible bug involving square roots simplifications?

I have the following code: ...
1
vote
1answer
15 views

Show result of matrix operation in terms of user defined matrices

I have defined some matrices K[0],K[1],...,K[9] and S[1],...
2
votes
0answers
29 views

How to Simplify/Factorise symbolic non-commutative expressions?

It always strikes me as odd, that Mathematica seems to have a hard time with non-communative multiplications. I can use the horrible TensorExpand (or more performant Distribute) to get ...
2
votes
2answers
111 views

FullSimplify a trigonometric expression doesn't work as expected

I know this kind of question is frequent asked, yet each case has its own particularities. I will show my problem. I define the following: ...
3
votes
1answer
25 views

How do reduce this expression

I spent quite some time trying to figure out why my answer was wrong, only to discover that it was right, just simplified in a way a very poor way in Mathematica: ...
0
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0answers
36 views

Calculate a definite integral containing an ExpIntegral

I need to calculate the following integral Integrate[Exp[-(y/bn)] (-y)^c ExpIntegralE[d, p y], {y, 0, z/x}] Where $z<0,z\in \mathbb{R}$, $x\in\mathbb{R},x>...
1
vote
0answers
28 views

Specify “Simplify” output to see steps

I have the equation: $$w=\frac{b(r+s)+\theta q(\theta) \lambda p}{r+s+ \theta q(\theta) \lambda } + \lambda \left(p - \frac{b(r+s)+\theta q(\theta) \lambda p}{r+s+\theta q(\theta) \lambda}\right)$$ ...
0
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0answers
27 views

Very simple algebraic FullSimplify/Simplify problem(s), without even assumptions

I did some digging about FullSimplify but did not find something concrete about my problems and I think they are too elementary to pass. EXAMPLES START 1)This example is not problematic but I will ...
0
votes
2answers
64 views

Looping through the FullForm of an expression? [closed]

Anyone have advice on looping through the FullForm ("expression tree") of an expression? I'd like to try some ideas for simplifying expressions by examining the FullForm, but I always have trouble ...
1
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0answers
56 views

Efficient evaluation of real/imaginary parts of long expressions

I have the following, rather compact, but complex, expression (see below). I simply want the real part of this. Now, when I do the usual, i.e., ...
1
vote
1answer
29 views

Mathematica is not simplifying trignometric functions under Abs although I provide assumptions

I am trying to simplify a simple expression, (1/2)*((-Pi)*Abs[Sin[t]] - Pi*Abs[Sin[t - 2*Pi]] - 2*Pi*Abs[Sin[t - Pi]] + 4) i.e $$ \frac{1}{2} (-2 \pi \...
3
votes
1answer
56 views

Simplify with Semi-Infinite Interval

I'd like to Simplify an expression using an Interval constraint. This question shows that you need to put the variable in a <...
0
votes
0answers
55 views

Complex conjugate of real number [duplicate]

I'm trying to take complex conjugate of some terms in a function. I tried this ...
0
votes
1answer
78 views

Fastest way to simplify rational functions

I am using Series to approximate function of two variables: Series[f[x,y],{x,0,m}] the function is a complicated sum of ...
2
votes
0answers
118 views

Substitution of expressions using Groebner basis

I know this topic came up numerous times (most of the results are detailed in the comments of this link Is there a way to to substitute for symbols, simplify, and back-substitute?). However, I have ...
0
votes
1answer
43 views

Simplify equation with two variables

I'm trying to simplify the following equation with respect to r: $-0.192852 + c1^6 (-21743.3 + 81452.7 r^{0.26297} - 379334.0 r^{0.32579} + 730090.0 r^{0.36131} + 18787.9 r^{0.38222} + 448129.0 r^{0....
1
vote
2answers
32 views

Clarity of assumptions in PowerExpand

I am trying to simplify a complicated expression which involves $\log$ of sum of $e^{i x_{i}}$ terms, and I found out that using PowerExpand it gets greatly simplified. But I know that PowerExpand ...
4
votes
1answer
80 views

How to convert Sine to Cosine?

I have some trigonometric quantities, which may be expressed in either sine or cosine, e.g., ia = Cos[wt], ib = -Sin[π/6 + wt], <...
1
vote
1answer
36 views

How to PowerExpand a generic Product?

I have: PowerExpand[Log[Product[f[i], {i, 1, n}]]] // InputForm (* Output: Log[Product[f[i], {i, 1, n}]] *) However, I would expect to get the following as the ...
0
votes
0answers
40 views

Copying very long expression to LaTeX

I have a long expression (even after using Simplify) which I am trying to copy to LaTeX using the "Copy to LaTeX" command. However, it is too messy for LaTeX to ...
0
votes
1answer
29 views

Testing dependent variables

I'm trying to test whether or not I can simplify a function using Mathematica. At first glance it seems there is a dependency of $w$ on $R_0$, but I'm wondering if Mathematica can help me remove this. ...
0
votes
1answer
44 views

Using defined function to simplify expression

I have an expression $\sqrt{1-6e^{ik}+e^{2ik}}$ I want to simplify this expression by defining $f(k) \equiv 1-6e^{ik}+e^{2ik}$ So that my output will be $\sqrt{f(k)}$ Thanks
1
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2answers
83 views

Reduce does not get a result

I try to solve the following inequation. ...
0
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0answers
30 views

Implicit assumption in simplifying an equation

So I tried simplify on an equation (see below). ( Laplacian[V[r,\[Theta],\[Phi]],{r,\[Theta],\[Phi]},"Spherical" ] //Simplify) % == 0 %//Simplify Now the weird ...
1
vote
1answer
56 views

How to force Mathematica to “Together” a fraction under a Log and a Square Root

Consider the following code: Assuming[2 > u > 0 && 2 > x > 0, FullSimplify[Log[x]/Sqrt[4 - x^2] /. x -> 2 Sqrt[(2 - u)/(2 + u)]]] The ...
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1answer
103 views
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0answers
109 views

Renaming one parameter changes the result of Simplify

Surely the following couple of expressions should both output True: ...
5
votes
1answer
689 views

Are these expressions not equal? Mathematica output is ambiguous

The following plot indicates that the first expression equals the second. But how can I use Mathematica to show that is true: ...
3
votes
1answer
109 views

Boundary Value Problem and FullSimplify

I'm confused about the output Mathematica is giving me when solving a boundary value problem of the form: ...
2
votes
0answers
47 views

Simplifying long expressions leads to memory allocation failure

I am currently trying to manipulate a number of expressions into a particular form that will allow me to determine their poles and zeros: ...
1
vote
2answers
64 views

Simplify differential expressions

One can differentiate a two dimensional vector like this, ClearAll["Global`*"] u[x_, y_] := {f[x, y], g[x, y]} Div[u[x, y], {x, y}] with output ...