Core language (Tutorial Collection) - pages 98 and 99

Questions
1

Dear:

Reading the Core Language cited above I typed the following instructions:

odeplot[de_, y_, {x_, x0_, x1_}, opts : OptionsPattern[]] :=

 Module[{sol},
  sol = NDSolve[de, y, {x, x0, x1}, 
    FilterRules[{opts}, Options[NDSolve]]];
  if[Head[sol] === NDSolve,
   $Failed,
   Plot[Evaluate[y /. sol], {x, x0, x1},
   Evaluate[FilterRules[{opts}, Options[Plot]]]]
   ]
  ]
odeplot[{y''[x] + y[x] == 0, y[0] == 1, y'[0] == 0}, y[x], {x, 0, 10}]

Unfortunatelly it did not work but it worked when I delete the If, as you can see bellow (Plts Attachded):

odeplot[de_, y_, {x_, x0_, x1_}, opts : OptionsPattern[]] :=

 Module[{sol},
  sol = NDSolve[de, y, {x, x0, x1}, 
    FilterRules[{opts}, Options[NDSolve]]];
  Plot[Evaluate[y /. sol], {x, x0, x1}, 
   Evaluate[FilterRules[{opts}, Options[Plot]]]]
  ]

Could you help me why does not work a simple program from Tutorial Collection ?

Thanks,
Ana

2

The “if” needs to start with the uppercase “I” as in “If”. All built-in Mathematica commands must start with uppcase letters.

3

Effectively (If) command must have the i capitalized, the rest seems okay, here is the example of your code running

odeplot[de_, y_, {x_, x0_, x1_}, opts : OptionsPattern[]] := 
 Module[{sol}, 
  sol = NDSolve[de, y, {x, x0, x1}, 
    FilterRules[{opts}, Options[NDSolve]]];
  If[Head[sol] === NDSolve, $Failed, 
   Plot[Evaluate[y /. sol], {x, x0, x1}, 
    Evaluate[FilterRules[{opts}, Options[Plot]]]]]]

Example

odeplot[{y''[x] + y[x] == 0, y[0] == 1, y'[0] == 0}, y[x], {x, 0, 10}]

2331Untitled-1.jpg
2331Untitled-1.jpg360×216 6.56 KB

Greetings

4

Where did you guys learn the syntax for the wolfram language? Also are there any ways to use it without the raspberry pi?

5

Wolfram Language is, basically, the language of Mathematica. (Present-tense verb, stay tuned.)

Two pages I often point newbies to are,

http://reference.wolfram.com/mathematica/tutorial/GettingUsedToMathematica.html

http://reference.wolfram.com/mathematica/tutorial/GettingStartedOverview.html

I see that there is a WL equivalent for the latter:

http://reference.wolfram.com/language/tutorial/GettingStartedOverview.html

6

Thank you!!!

7

it would be more accurate, i think, to say that Mathematica was the first knowledge domain in which the Wolfram Language was used. WL is a stand-alone programming language (i have programmed in it for 28 years and have only used a mathematical function one time). it is applicable to MANY fields besides mathematics and physics and engineering - in fact, to ANY field in which computation is employed.

8

Ally Clinton,

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