Linked Questions

9 votes
4 answers
810 views

Numerical instability in cosh and sinh - integral functions [duplicate]

I'm trying to calculate the function: CoshIntegral[x] Sinh[x] - Cosh[x] SinhIntegral[x] Unfortunately Mathematica seems to hit a point (x~20) and things become ...
jake's user avatar
  • 93
3 votes
1 answer
6k views

How to increase precision: $MinPrecision does not help [duplicate]

I have the following series: ...
Anixx's user avatar
  • 3,630
8 votes
1 answer
514 views

ReplaceAll[] and Limit[] don't give correct results for this expression under extreme variables [duplicate]

Possible Duplicate: Funny behaviour when plotting a polynomial of high degree and large coefficients 1/x^2 + (3 + x)/(6 (1 - Exp[x] + x)) ——This is a ...
xzczd's user avatar
  • 67.1k
1 vote
1 answer
1k views

Relative error plot [duplicate]

I was plotting the relative error of the $e^{11/12 -n}n^{n+1/2}$ approximation to $n!$ as $n$ gets larger and larger, and at some very large value of $n$ Mathematica gives this plot: Can somebody ...
George's user avatar
  • 13
2 votes
1 answer
192 views

plot of polynomial expression failed [duplicate]

I want to plot a polynomial expression for {a,0,1}: ...
Gae P's user avatar
  • 657
3 votes
1 answer
384 views

Dealing with square roots [duplicate]

Consider following expression: $$ \sqrt{-\left(2 \sqrt{x^{-8/3}-x^{-4/3}+1}\, x^{4/3}+5\right) x^{4/3}+4 \sqrt{x^{-8/3}-x^{-4/3}+1}\, x^{4/3}+2 x^{8/3}+5} $$ In code: ...
stinglikeabeer's user avatar
2 votes
1 answer
182 views

Strange behavior when replacing variables by numerical values [duplicate]

I have a rather complicated function with parameters {a, b, c, d, e, f, k}, and I'd like to know its behavior as a function of k alone given other parameters, so I try the following code: ...
Leo Fang's user avatar
  • 754
0 votes
0 answers
99 views

Why is PolyLog[] giving weird answers for ordinary values? [duplicate]

Possibly related to this question, but it seems slightly different: Strange behaviour of PolyLog Function Wikipedia says that for real s, z<1 should be real. So I was confused when MMa returned: ...
F dot Floss's user avatar
0 votes
0 answers
77 views

Matrix ODE gives badly-behaved numerical solution [duplicate]

I am trying to solve matrix ODE: ...
Jieyu You's user avatar
27 votes
6 answers
5k views

Annoying display truncation of numerical results

I have a lot of data to inspect. An example of a number in my program is 123.189094 This gets displayed as 123.189 ...
Reb.Cabin's user avatar
  • 8,693
58 votes
3 answers
6k views

Is manual adjustment of AccuracyGoal and PrecisionGoal useless?

This is a problem confusing me for years. AccuracyGoal and PrecisionGoal are two options that I never truly understand and, to ...
xzczd's user avatar
  • 67.1k
12 votes
4 answers
1k views

Complex result for real vectors in VectorAngle

Bug introduced in 10.0 or earlier and fixed in 12.0.0 or earlier I was expecting a real angle using VectorAngle when passing real valued vectors, but I obtained a ...
Adam Law's user avatar
  • 143
26 votes
2 answers
2k views

Different floating-point numbers equal?

Let's define two different numbers. x = 1. y = 1. + 2^-52 (* equivalently, 1 + $MachineEpsilon *) Let's make sure they're different with ...
2012rcampion's user avatar
  • 7,851
9 votes
2 answers
3k views

A problem about function N

Toady,I have a problem about N,described as below: For example N[1/3, 5] (* ==> 0.33333*) and ...
xyz's user avatar
  • 635
9 votes
3 answers
2k views

Very different results from evaluating same expression with different precisions

When I evalute the following expression, ...
MATIRMAK's user avatar
  • 749

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