Problem 813. Multiply 2 numbers

Created by Aurelien Queffurust

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{"relationships":[{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/document","relationshipId":"rId1","target":"/matlab/document.xml"},{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/output","relationshipId":"rId2","target":"/matlab/output.xml"}],"parts":[{"partUri":"/matlab/document.xml","relationship":[],"contentType":"application/vnd.mathworks.matlab.code.document+xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\"?><w:document xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\"><w:body><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Very easy, you just have to multiply 2 numbers but you cannot use the following signs (*, /, - ,^) ,mtimes , times, cross, prod, cumprod , dec2bin, int2str and num2str functions. Will you take up the challenge?!</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>Example : x= 3; y= 2;</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>output = 6 since 3*2 = 6 :)</w:t></w:r></w:p></w:body></w:document>"},{"partUri":"/matlab/output.xml","contentType":"text/xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\" ?><embeddedOutputs><metaData><evaluationState>manual</evaluationState><layoutState>code</layoutState><outputStatus>ready</outputStatus></metaData><outputArray type=\"array\"/><regionArray type=\"array\"/></embeddedOutputs>"}]}

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1980 Solutions
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Last Solution submitted on Aug 05, 2020

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Aurelien Queffurust on 9 Jul 2012

As Richard made me notice by email, tests 5 and 6 (using randi and non-integer) were not enable. As I have rescored all solutions, some previous solutions which passed the test, do not pass it anymore.

James on 9 Jul 2012

Can you please set a tolerance for the submitted answers? Using exp(log(x)+log(y)) fails nearly all possibilities for test case 5, with the biggest error being roughly 2.5e-11.

Ilias Patelakis on 24 Oct 2017

Nice one. It would be more challenging to add a test case where both function arguments are decimal numbers. :)

Jiahang Li on 4 Feb 2018

You can try adding, and something wonderful happens.

Solution Comments

Solution 1445729

1 Comment

1 Comment

md.wahid tousif_rahman on 21 Feb 2018

Most foul one

Solution 1433565

1 Comment

1 Comment

Jiahang Li on 4 Feb 2018

funny~

Solution 1117273

1 Comment

1 Comment

Jess Stuart on 8 Feb 2017

exp(log(x)+log(y)) works with a trivial amount of roundoff error. Matlab is a numeric language. Using Isequal() is dumb.

Solution 415606

2 Comments

2 Comments

Dimitrios on 8 Mar 2014

i cant understand why test 1 fails :/

Aurelien Queffurust on 10 Mar 2014

It fails because you use the minus sign and there is the following test :
assert(isempty(strfind(filetext, '-')))

Solution 362049

2 Comments

2 Comments

Ramoflaple on 11 Aug 2015

good use of 'linspace'

David Verrelli on 10 Nov 2017

What if _both_ x _and_ y were either negative or non-integers though?

Solution 250534

2 Comments

2 Comments

Kumar on 29 May 2013

Test 1 is always showing Fail. This is disgusting. May be some error on the creator part. Kindly check...

Ned Gulley on 29 May 2013

The error for Test 1 says "Output argument 'output' (and maybe others) not assigned". Close examination of your code reveals that when x is 1 and y is 2, you go down the first switch of the outer "if" statement, and sure enough, output never gets assigned and the function fails.

Solution 106284

1 Comment

1 Comment

David Young on 4 Jul 2012

Only works for scalars of course.

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multiplication product

Problem 813. Multiply 2 numbers

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Problem 813. Multiply 2 numbers

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