## 3010 Reputation

19 years, 251 days

Dr. Robert J. Lopez, Emeritus Professor of Mathematics at the Rose-Hulman Institute of Technology in Terre Haute, Indiana, USA, is an award winning educator in mathematics and is the author of several books including Advanced Engineering Mathematics (Addison-Wesley 2001). For over two decades, Dr. Lopez has also been a visionary figure in the introduction of Maplesoft technology into undergraduate education. Dr. Lopez earned his Ph.D. in mathematics from Purdue University, his MS from the University of Missouri - Rolla, and his BA from Marist College. He has held academic appointments at Rose-Hulman (1985-2003), Memorial University of Newfoundland (1973-1985), and the University of Nebraska - Lincoln (1970-1973). His publication and research history includes manuscripts and papers in a variety of pure and applied mathematics topics. He has received numerous awards for outstanding scholarship and teaching.

## Mathematica's second solution is a solut...

Mathematica's second "solution," namely, Y2=(x+2)^2 does not satisfy the ode for x>-2.

Indeed, substitution into the ode yields on the left, -x*(x+2), but on the right, x*abs(x+2). (Please note that the symbol sqrt(u) is a single positive number. It does not mean the pair of numbers +/-.)

A graph of the left and right sides shows that the two sides match for x<= -2, and for x=0. And nowhere else.

## Either one works...

I noticed your question to the OP, and the lack of a clear response to it. However, as far as my experience goes, the missing ingredient was the Suppress command from Typesetting. I had immediate success with D(f)(x)(0) and did not question whether there might be an even simpler form. Thanks for pointing that out.

## There's always more to the story...

Scot,

My ODE webinar in the Clickable series (check Youtube) has a pretty sophisticated eigenvalue problem solved numerically. And it's all done with point-and-click operations (2D math, palettes, Context Panel).

When exploring how I might solve a problem in Maple, I often try stuff via the Context Panel, thus avoiding the need to name things, look up syntax, etc. The ease-of-use features are useful.

The transition from point-and-click to learning commands is (in my view) easily done if the Context Panel is invoked in a worksheet where the underlying commands are then displayed. A user doing that can then determine if it's worth learning the syntax or not. Might even learning it without trying to.

I guess the bottom line is that when faced with a computational task, one asks "How do I do thus-and-such in Maple?" It's at that point that the ability to experiment, look things up, try things comes into play. And since Maple 10 when the Context Menu began to be useful, I've found the syntax-free tools to be more and more helpful.

## Maple usage alternatives...

Scot, thanks for dragging me into what might become an endless morass. So, let me just say my piece and point out that I will not be drawn into the fray any further.

I had 15 years experience with Maple in the classroom at a time when learning syntax was the only way to go. It was a chore convincing students to learn the Maple language in order to "learn the math language." When Maplesoft introduced the beginnings of "syntax-free" computing, I was then working for Maplesoft and I immediately saw the benefits of students not having to learn syntax in order to implement math calculations. I pushed Maplesoft to improve its capabilities in that direction because I believed it would benefit students.

For students who will make use of Maple far into their careers, learning syntax is probably necessary. But for students who need Maple to "get through" their required math courses, and who will probably not take math courses beyond those, why add the burden of syntax if it can be avoided?

For the instructor who wants students to master syntax, just operate in a worksheet (even using 2D math input) and use a Context Panel operation. The underlying syntax will be displayed. Is there a faster way to learn syntax?

So, I guess the moral of the story is that necessity is the mother of invention. Adopt the usage that best serves the student. And now we can debate the meaning of "best."

PS. I think what Paul did to solve the inequalities was clever, and the graph he drew meaningful (if not subtle). That he was smart enough to ask if there was a better way shows what happens when there's a tool allowing different approaches to be implemented.

## Built-in Programming Guide?...

Have you looled at the built-in Programming Guide, available in the help system?

## Imaginary unit, assignment operator, and...

The assignment operator in Maple is :=, not just =.

The imaginary unit is upper-case i, so it looks like I in this font.

The construct i(... needs to be changed to I*(

Generally, you want to apply the evalc command to a complex espression to break it into its real and imaginary parts. When I tried that with h1*h2, the resulting expression got very large, and it was evident that the sizes of a and lambda determined the form of the result. You will have to make appropriate assumptions on these parameters to achieve any kind of useful outcome.

## try this...

add in the command "with(plots)" so you get access to implicitplot3d, then change Kitonum's Explore command to

Explore(implicitplot3d(A=c,x=0.01..5,y=0.01..5,z=.01..5,axes=frame,grid=[15,15,15]),c=-1.2..0.)

You will get an animation of some of the level surfaces. You will have to modify the bounds and ranges to fit your needs.

## Calculate the correct Wronskians...

The "sub-Wronskians" cannot be calculated as 3x3 matrices with one column zero. Check the definitions of W1, W2, and W3. They are the determinants of appropirate 2x2 matrices formed by deleting the i-th row and column from the Wronskian matrix W, thereby defining W_i.

## Output of shilled fraction...

Both work-arounds eliminate the long fraction bar, but neither actually produces the "textbook" version (a+b)/c. But I guess the second uses the least horizontal space.

## Typesetting Assistant is in the View men...

Although the tool in question is called an Assistant, it has always been housed in the View menu, never with the other tools that are also called "Assistants."

Back in Maple 2015, the Typesetting Assistant required the user to manually set typesetting to "extended." In Maple 2019, the default for typesetting is already "extended" so the Typesetting Assistant works directly.

## Provision for the kerf must be made...

This solution is easy for the woodworker because all pieces can be cut "straight through." And it is an amazing piece of mathematics.

Unfortunately, provision for the saw kerf, at least 1/8", has not been made. Perhaps one should add the dimension of the kerf to all measurements, but there are pieces that would then end up oversized. Some woodworkers discount the squareness of 4x8 sheet goods and waste the factory edges as a matter of course. The stock-cutting problem is not easy!

## Subscripts as partial derivative operato...

Perhaps this post from December of 2010 is relevant.

https://www.mapleprimes.com/maplesoftblog/100265-Subscripts-As-Partial-Differentiation-Operators

It summarizes a Reporter article from July of 2010.

## MathType...

Because you say the equation in Word has to be editable, you can't just copy/paste - that results in an uneditable graphic.

Look into the program MathType that sets equations in an editable form in Word. I think the connection is that MathType understands LaTeX, and Maple can export the LaTeX form of its equations.

It's been about 20 years since I operated in that world, so forgive me if I'm in error on any of these points.

## Maximize is in Optimization package...

Since the Maximize command is part of the Optimization package, the usage in your check.mw worksheet should be

Optimization:-Maximize(...

If you first load the package via the with(Optimization) command, then the Maximize command will work as it appears in the check.mw worksheet.

## Is it executable math?...

We're just guessing here. Perhaps the last expression (x+4-2) lost it's "executable" tag. So, right-click on the expression and inspect the pop-up that results. There's a line "Executable Math" in the pop-up. If there's no check at the left of this line, then what was clicked on is not executable math. Also, executable math will be in a blue-tinged box but non-executable math will be in a gray-tinged box.

Next time you have a difficulty, post the worksheet in which the difficulty occurred. We'd all have a better chance of diagnosing an error if we could test the worksheet, not just an image of it. Use the green upwards-pointing arrow in the toolbar to upload a worksheet.

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