## One Badge

4 years, 267 days

## Evaluating expression/function...

You can use 2 alternative ways. But, with built-in math. functions defined on R (as e.g. sin), you have to write the argument as a float number (see g

1. As an expression, while using variable assignment:

f := 2*sin(x)-x^2/(10.00);  x := 5. ; f ; unassign('x')      gives  -4.417848549

Note: the command "unassing('x')" is just a precaution for not keeping the assigned value of 'x' fo further computations.

2. As a function: it's better for further use, as Kitonum 9667 says.

f :=x->2*sin(x)-x^2/10.00;  f(5.)  gives -4.417848549

whereas f(5) gives only   2*sin(5)-2.500000000.

You can see the following:

sin(5) gives  sin(5);   else you have to do  evalf(sin(5)) to obtain the value.

whereas sin(5.) directly gives -.9589242747 ;

## DTM...

Dear mj17515

I apologize, but solving differential equations is really not my cup of tea, and I do not even know the Differential Transform Method. In these conditions (as usual, as one finds almost always answer in the Web :), I typed in Google: "Differ.…..Method" and obtained several linsks, e.g.:

http://www.m-hikari.com/ams/ams-2011/ams-69-72-2011/mirzaeeAMS69-72-2011-2.pdf.  It includes much explications and theorems, where one can see Dirac delta function is effectively involved in some cases.

http://www.sciencedirect.com/science/article/pii/S0307904X07002247.  The donwload is free, and in ref. list, the #[16] indicates method using Maple !  Its download is not free, but you get it if you have university bib. commodities. Just for curiosity: For what subject, do you need this equation?

JLP

Note: there are much infos on differ. equ. in Help pages of Maple.

## DTM, question 1. :Dirac function...

Hi,

Maybe the help page "Dirac" could answer your 1st question. The Dirac function is applied by "Dirac (opts)",

it can be one-dimensional, k-dimensional, nth derivative, ...

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