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Solution of formula in Wolfram|Alpha?

Posted 4 months ago
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Hello,

I'd like to know how I should input formulae for transposition in Wolfram|Alpha and would be grateful for some help. I can do this in Mathway, but I'm finding Wolfram|Alpha less easy to use.

Ian

POSTED BY: i d
Answer
15 Replies
Posted 4 months ago

I'm surprised that there's been no response to the above, I thought there would've been a simple answer. Perhaps this information already exists somewhere, maybe in a manual or other document, if so, can anyone direct me to it please?

Ian

POSTED BY: i d
Answer

This works for me:

transpose of {{a,b},{c,d}}

What do you have in mind to do with transposition?

Posted 4 months ago

Thanks for the reply.

I have a few questions about your example:

I'm not sure what 'transpose of {{a,b},{c,d}}' is asking, is it a matrix?

The use of your instruction 'transpose of' is interesting, I was just using 'transpose'. How can I learn the correct syntax required for WA, is there a list of commands available?

I don't have a specific formula in mind but want to better understand how to use WA to, transpose, for instance. If I wanted to transpose a=b^(c/d) for d, how would I input this to get the answer and step by step instructions?

Thanks again for sharing your method.

Ian

POSTED BY: i d
Answer

I just found this page that may help you: examples for matrices

Posted 4 months ago

Thanks for the link but it doesn't address my questions.

I'm looking for examples of how WA provides step by step transpositions of formulae and have given an example of such.

I'd also like to know how I can learn the specific form of input that WA requires, e.g. why it is necessary to type 'transposition of' and not just 'transpose'.

It might be possible that I am expecting to much from WA.

I am not looking for examples of matrices.

Ian

POSTED BY: i d
Answer

What do you mean with "transposition of formulae"?

Posted 4 months ago

It means rearranging a formula or equation to an equivalent form and is useful for finding unknown variables.

I gave an example in one of my previous posts.

e.g. Is it possible for WA to transpose a=b^(c/d) to make d the subject?

Here's a link to a free online transposition tool

POSTED BY: i d
Answer
Posted 4 months ago
Posted 4 months ago

Thanks for the example Hans.

You demonstrate a good knowledge of what instructions WA is able to recognise (ie 'Solve' and the >0 conditions) which establishes WA's ability to compute bespoke calculations rather than just plugging values into template examples. How did you learn to do this and what advice can you offer to anyone else hoping to input their own problems?

Can the steps of your transposition be shown?

Ian

POSTED BY: i d
Answer
Posted 4 months ago

Thanks. I very seldom use W|A. The wording of my query was probably influenced by the fact that I am familiar with Mathematica.

The rewriting ("transposition steps") can easily be made by hand once exp and log is understood. Nothing special, computer aid is not really needed.

Posted 4 months ago

I'm grateful for your example and agree that such a transposition is do-able without the use of WA. I really just used it to see how to instruct WA and get familiar with its language. What I've learned from this thread is that WA presupposes a level of knowledge that I do not yet have. Fortunately for me and others like me, there are a lot of alternatives online to choose from.

Thanks for taking the time to help.

POSTED BY: i d
Answer
Posted 4 months ago

I entered a transposition into WA and it returned this...

enter image description here

The correct answer, which has now been verified by the tutor, should look like the below (BTW - I have used the term 'Is' here and 'x' in the WA example above.)

Does anyone know why WA did not return the correct result?

enter image description here

POSTED BY: i d
Answer
Posted 4 months ago

WA and your tutor actually gives the same solution. The solutions are in different forms, but they give the same numerical result.

Wolfram|Alpha:

enter image description here

The n parameter reflects the fact that ArcSin is multivalued. Here it is set to zero because the angle we are looking for is in the first interval, -pi/2 to pi/2.

Tutor:

enter image description here

Posted 4 months ago

Thanks for the explanation.

Do you know if there's any way to get the preferred form... enter image description here

From the original form.. enter image description here

I'm not sure what 'arcsin is multivalued' means but I don't see how it affects the required task which is to 'Rearrange for t'. Perhaps its because I'm using the command 'Solve of''. What command could I use to ask WA to 'Transpose' or 'Rearrange' for another variable without giving a solution that I don't want?

POSTED BY: i d
Answer
Posted 4 months ago

I am able to do it in 2 steps

1. Isolate t:

enter image description here

2. Set n to zero and simplify:

enter image description here

Which is equal to: $$\frac{\cos ^{-1}\left(\frac{x}{13}\right)+\frac{\pi }{4}}{2 \pi }$$

As I said before I do not have much experience with WA. Maybe there is some way to do this two step rewriting in a single step.

Finally:

What command could I use to ask WA to 'Transpose' or 'Rearrange' for another variable without giving a solution that I don't want?

That would be like telling WA to do its job "just right". I dont know how to do that.

Hans

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