Questions tagged [simplifying-expressions]
Questions on manipulating complicated expressions and making them look simpler using Simplify, FullSimplify and Reduce.
1,799
questions
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14 views
Uncertain behaviour when using FullSimplify
While doing some (symbolic) calculations with Mathematica, I encountered a small problem with the FullSimpilify function that hopefully someone here might explain to me. More specifically, I fear that ...
2
votes
1answer
85 views
How to simplify Elliptic integrals?
Context
I would like to show that these 2 functions are identical
...
0
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2answers
37 views
Expression simplification
I have this term
Sqrt[(B Bc)/(A^2-B Bc)]Sqrt[B Bc+A(-A+Sqrt[A^2-B Bc])]Sqrt[-B Bc+A(A + Sqrt[A^2-B Bc])],
which actually can be simplified to B*Bc. However, it ...
1
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0answers
39 views
What is the difference between NSolve and N[Solve] [closed]
N[Solve]
NSolve
I am getting different results everytime I use these commands.
1
vote
1answer
58 views
Getting full expression of real roots using ToRadicals?
I'm solving this system of equations with Mathematica:
...
3
votes
1answer
33 views
Stopping Simplify and FullSimplify expressing real terms as complex
I am working with real functions but FullSimplify and Simplify express them as complex terms. I assume this is because the ...
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0answers
28 views
Simplify with Assumptions: Puzzle for 4 variables [duplicate]
I have a rather specific question about Simplify[] (hope this is not off-topic).
The puzzle I have is that Simplify[] with ...
1
vote
0answers
34 views
Recognizing Padé approximant in Simplify/Refine
Having used Maple before, I know for a fact that there we can just type in a function, then separately define its Padé approximant (or Taylor) and then use simplify ...
0
votes
2answers
50 views
Computing the coefficients of series
I am trying to fully expand the following
$$\sum_{n=0}^{\infty} \frac{q^{\frac{n(n+1)}{2}}}{(q;q)_n}$$
Which when expressed in Mathematic is: q^(n*(n + 1)/2)/QPochhammer[q, q, n]
I would like to be ...
1
vote
1answer
80 views
Symbolic solution of system of equations 12x12 takes very long time and the answer is complex too
I am trying to solve a system of equation symbolically. It works fine for 6x6, however for 12x12 system it takes very long and the answers are complex. I am using "Solve" or "Reduce&...
1
vote
2answers
99 views
How to eliminate $x,y$ from that system?
The system is as follows
sys={a*Tan[x] == b*Tan[y], a*Sin[x]^2 + b*Cos[x]^2 == m, b*Sin[y]^2 + a*Cos[y]^2 == n}
My approachs are
...
0
votes
1answer
62 views
Write a^2k =0 for k in natural numbers [closed]
How do I write $a^{2k}=0$ where $k \in \mathbb{N}$ as an initiation to a problem simplification? I tried writing {k,0,N} as a part of code, which is not detected
0
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1answer
52 views
Simplification of array terms
My $n$th term in an array is an expression, something like $v=\{0,a^2+2,\frac{2ab}{5}-\frac{a^3}4,\frac{2abc}{3}-\frac{a^3}4,...\}$. As the array length increases, the number of variables involved ...
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0answers
25 views
Simplify Equation with variable unequal to zero
How can I simplify the following equation with Mathematica assuming z!=0?
I have the following code:
...
1
vote
0answers
43 views
How to simplify this output with ArcTan[Tan XXXX ] [closed]
Integrate[Tan[3 x]^2, x]
Why couldn't it simplify the answer to
-x + 1/3 Tan[3x]
so to speak
2
votes
1answer
43 views
Simplify square roots with five or more variables, assumptions not working
Mathematica 12.0 gives me a result of the form
Sqrt[a b + x y z] Sqrt[-(1/(- a b - x y z))]
which obviously should simplify to 1. However, even with the assumption
...
0
votes
1answer
56 views
How can I get rid of Abs?
In the following code, the functions WP[t] and WS[t] are real. Time also is a positive parameter. As you can see, MATHEMATICA enters Abs in the calculations. Including Abs only complicates the next ...
2
votes
3answers
119 views
Simplifying expressions containing binary variables
Consider an expression with two binary variables, $a,b\in\left\{ 0,1\right\} $, given by $F=(1-a-b)^{3}(1-b)$, with truth table:
...
2
votes
2answers
81 views
How to force Mathematica to simplify this expression?
I have the following expression
$$2^{1-2 n^2} \left(3-\sqrt{5}\right)^{-n-1} \left(\sqrt{5}-1\right)^{n (n+1)} \left(\sqrt{5}+1\right)^{n^2}$$
This can be simplified to
$$\left(\frac{1}{2} \left(\sqrt{...
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0answers
19 views
Applying Function Using // with additional arguments [duplicate]
I was trying to apply functions at the end of an expression, for example:
expr //Simplify
But sometimes I need additional arguments for ...
0
votes
0answers
36 views
how can I correct this code? [duplicate]
I need to calculate matrix m1 according to following algorithm. Then, I have to put it in the differential equation. However, matrix m1 is complex and therefore the differential equation does not work....
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0answers
40 views
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0answers
51 views
How can I correct this code to get an answer? [duplicate]
I need to calculate matrix m1 according to following algorithm.
Then, I have to put it in the differential equation.
However, matrix m1 is complex and therefore the differential equation does not work....
1
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1answer
32 views
Expanding and sympifying an expression when using typesetting format
I'm starting to learn Mathematica, and in the book that I'm reading the author presented the commands Simplify and Expand. Now, ...
2
votes
1answer
86 views
Mathematica and its default assumptions
I am a bit surprised that evsluating
Integrate[Exp[I n x],{x, 0, Pi}]
gives
$\qquad \frac{-i(e^{in\pi}-1)}{n}$.
What if $n = 0$? I didn't assume anything about $n$ ...
0
votes
2answers
177 views
Can the error function be expressed in terms of other special functions?
I obtained with Mathematica some results written in terms of the error function Erfi[x].
Is there is a way to transform the error function into other special functions e.g. Bessel functions or ...
3
votes
5answers
197 views
Simplifying away imaginary part
I'm solving the following eigensystem, and I get result which looks complex-valued. I expect the result to have 0 imaginary part, can anyone see a way to simplify it away?
...
1
vote
2answers
85 views
How to simplify an equation corresponding to an ellipsoid? [duplicate]
The equation
29/36 - x/2 + x^2/4 + y/9 + y^2/36 - (4 z)/9 + z^2/9 == 1
is equivalent to
...
2
votes
0answers
49 views
Exact value involving ProductLog
By manual manipulation, it's not too difficult to show that the value of the following expression is exactly $1.$ How to convince Mathematica to do the simplification?
...
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0answers
28 views
Shorten a sum of many terms by introducing a rule for scalar product and Kronecker deltas and using repeated replacements
There is a sum of many terms that I would like to simplify by introducing a notation for scalar product of two vectors. Each term is a product of constants and of several components of 3D vectors: <...
1
vote
1answer
50 views
Use the fact that $u(t)\cdot u'(t)=0$ for $u\in\mathcal{S}^2$
If for all $t$, $u(t)$ is a point on the unit sphere $\mathcal{S}^2 \subset\mathbb{R}^3$, $u'(t)$ is orthogonal to $u(t)$, because $u'(t)$ is in the tangent plane of the sphere.
I have large ...
1
vote
1answer
43 views
When numbers plugged in - this expression evaluates to zero, but otherwise will not evaluate to zero
I have the following code:
...
7
votes
2answers
288 views
How to select several columns from a dataset
I have a dataset with 20 columns. For a analysis I need all columns except the columns 9 and 11. What I do is:
...
0
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1answer
72 views
Fullsimplify not working perfectly [closed]
Here I am using the below code for a simplification.
...
2
votes
3answers
94 views
force maximum simplification of radicals in a traditional way-How to do it?
this should be simple but I can't get mathematica to simplify a radical or a set of radicals and express them in the traditional way
for example by simplifying this
...
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2answers
57 views
Inverse function and Integral: How to simplify this DSolve output?
I'm trying to DSolve these equations with each other:
...
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0answers
36 views
Solving a system of inequalities where some of the variables are integer-valued, and some are real-valued [closed]
I'd like to know how to ask the Reduce command to solve over one domain for certain variables, and another domain for other variables. For example, I'd like to solve the system of inequalities
$$ 2 a +...
1
vote
1answer
61 views
Extracting subexpressions
This is a recurrent topic: replacing subexpressions. See for instance:
...
2
votes
2answers
84 views
How to Simplify expression efficiently inside Power
How can I simplify trivial expressions under the Power?
Here is one example:
(z2p-z2p z3)^-ϵ
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2
votes
1answer
45 views
How to protect the expansion of exponent while applyting rules
I am trying to separate/split an expression (consisting of polynomials) to a list. However I want to keep the exponents intact. Here is an example:
...
2
votes
0answers
51 views
How to simplify a matrix with detailed steps?
When I simplify a matrix with a parameter, for example:
(PS: it's the answer to the textbook)
When I use RowReduce[] to simplify this matrix. it seems going too far to its simplest form:
So, My ...
0
votes
0answers
44 views
Constant inside If condition
I hope you are doing well.
I am currently writing some code in which I have an If statement where I will be dividing two expressions and checking to see if the quotient comes out to be a constant ...
0
votes
1answer
77 views
How to symbolically integrate a function of 6 variables?
I have a big function of 6 variables in total - x1, x11, x2, x22, x3, x33.
...
2
votes
1answer
40 views
How to simplify quotient and mod in integer domain
I want to simplify (a*32 + a%32)/32, and a is integer.
So I write:
...
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0answers
48 views
Simplification and patterns
I have a very simple simplification to make, where I need to do a replacement but the pattern matching seems slightly awkward.
I would like to simplify:
...
0
votes
1answer
41 views
How to imitate the operation law of vector
Given that $(a \times b) \cdot c=2$, now I need to find the value of $[(a+b) \times(b+c)] \cdot(c+a)$.
...
0
votes
1answer
55 views
How to simplify an expression to a variable?
So I'm doing some operations in Mathematica and I arrive to this expression:
...
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0answers
34 views
How to simplify huge expressions when the final form is known?
I am solving a system of equations of the following type:
$$a_1 \cdot f[13,0] + b_1 \cdot f[13,1] + ... + k_1 \cdot f[13,11] + l_1 (d[12] - f[13,12]) = m_1, \tag{1.1}$$
$$a_2 \cdot f[13,0] + b_2 \cdot ...
5
votes
0answers
70 views
Wrong results from FullSimplify[Exp[-2 (x - 3.1)^2]] [duplicate]
I notice the following weird results with MMA version 12.1 on Mac. I restart MMA and still get the same.
...
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2answers
65 views
How to sort out/ extract positive and negative powers as list?
I have the following expression
expr = x1^d1 * x2^d2 * x3^d3;
where d1,d2,d3 can contain negative values/expression i.e. in ...
