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2h
comment Testing for a vector of reals
David, your solution returns True for realVector[{1, 2, 3}], I think the OP wants this to return False. This happens because integer also returns True for Element[#,Reals], so a Head test is needed.
2h
answered Testing for a vector of reals
4h
comment User Input Through Dynamic
a small MWE example will help.
4h
reviewed Approve Testing for a vector of reals
1d
answered Generating a Variable Number of Dynamic Variables
1d
comment What's real analogue for FromDigits?
RealDigits? as in RealDigits[ToExpression["1234.234532"]] gives {{1, 2, 3, 4, 2, 3, 4, 5, 3, 2, 0, 0, 0, 0, 0, 0}, 4}
2d
comment Problem with control structures on getting root values on array
it is not too clear what you are asking. But why not create the list you want, and at the end use DeleteDuplicates to remove duplicates.
2d
comment Maximize[Cos[x - 1], x] is not evaluated
Strange. Wonder why this works Maximize[Cos[x - 1.], x] giving {1., {x -> 1.}}
2d
comment ControlType -> None Vs. Module inside Manipulate (i.e. making everything local)
If you make the variables local to a Module inside Manipulate expression, then their values are no longer saved between refreshes of the expression. So you can't use them to store counters and other values that you want to remain saved as the simulation is running. Basically a new clean copy of these variables are made each time the expression is refreshed. So, rule of thumb: If you want to save the value of something between refreshes, you need to use {{x,0},None}. For (2), you should not make variables in Initializations. Only function definitions. Variables there become global.
Jan
19
comment Evaluate the Limit
Try Limit[((1 + 3 x)/(1 + 4 x^2 + 3 x^4))^3, x -> 1] this gives 1/8
Jan
19
revised Differential equation with a Heavisidetheta function running for ever
deleted 15 characters in body
Jan
19
answered Differential equation with a Heavisidetheta function running for ever
Jan
19
comment How to define a real symbolic variable
You can use Assuming[Element[{a, b}, Reals], Simplify[sol]] in mathematica, you do not declare a variable of a type. It is not like C or Pascal.
Jan
19
revised Solving a second order non-linear differential equation
typo
Jan
19
comment Solving a second order non-linear differential equation
@Dr.WolfgangHintze For a symbolic solution try to DSolve the ODE without initial conditions. You will find the Inverse function of Integrals containing the error function Erf On which version M gave solution to this? Using version 10.02, it does not. It returns unevaluated. screen shot: !Mathematica graphics
Jan
19
answered Solving a second order non-linear differential equation
Jan
18
comment PDE: Solving Burgers' equation with initial value given by a self consistency equation
the function $m(x)$ is defined in terms of itself?
Jan
17
awarded  Yearling
Jan
17
answered Integrating a compound expression
Jan
17
comment Integrating a compound expression
M can't find analytical antiderivative. you can try different upper limits, build table of data, and try to do an interpolation function of the result.