Here is something taken from what I wrote in my notes on my phone a long time ago...
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a + b = 10a + b Divide both sides by a
a/a + b/a = 10a/a + b/a
1 + b/a = 10 + b/a Subtract b/a from both sides
1 = 10
So you'd be like, "NO SOLUTION!!!" right??? WRONG!! because a = 0 IS a solution to the original equation, but when you divided both sides by a it made it look like there was no solution. So that is why you gotta always say a ≠ 0 whenever you divide by an unknown number. So then the final answer would be basically saying "No solution when a ≠ 0. So a = 0 might be a solution might not be I dunno." Then you gotta check if a = 0 is a solution.
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So that is why 0 is missing from your list.
When you divided both sides by b, you didn't note that the following equation holds only when b ≠ 0
Otherwise, it is true that ab = 36
There are three solutions to this system of equations (see here) and in both cases where b ≠ 0, ab = 36
But ab = 36 is not the full story! There are more restrictions...
Notice that (1, 36) can't be a solution for (a, b) because
a + ab2 must equal 40b but 1 + 362 ≠ 40(36)
So (1, 36) can't be a solution.
There are more restrictions on a and b besides just ab = 36 ( when b ≠ 0 )
In order from oldest to newest:
Answers by CPhill and me: | https://web2.0calc.com/questions/help_49470 | |
Second answer by CPhill: |
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Answer by heureka: | ||
Second answer by me: |
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Found from first page of search results here. |
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Out of curiosity, I wanted to see a length comparison between your answer and my answer:
\(\cot(\arctan(\cos(\arctan(\cot(\arctan(\cot(\arctan(\cos(\arctan(\cot(\arctan(\cot(\arctan(\cos(\arctan(\cot(\arctan(\cos(\arctan(\cot(\arctan(\cos(\arctan(\cos(0)))))))))))))))))))))))))\)
25 total basic functions
Here is WolframAlpha's result: https://www.wolframalpha.com/input/?i=cot(arctan(. . .
versus
\(\cot(\arctan(\cos(\arctan(\cos(\arctan(\cos(\arcsin(\cos(\arctan(\cos(\arcsin(\cos(\arctan(\cos(\arctan(\cos(0)))))))))))))))))\)
17 total basic functions
Here is WolframAlpha's result: https://www.wolframalpha.com/input/?i=cot(arctan(. . .
.
.
(c)
Let's define functions a, b, and c like this:
a(x) = cot( arctan(x) ) = \(\frac1x\) where x is any real number except 0
b(x) = cos( arctan(x) ) = \(\sqrt{\frac{1}{x^2+1}}\) where x is any real number
c(x) = cos( arcsin(x) ) = \(\sqrt{1-x^2}\) where x is a real number the interval [-1, 1]
We start with 0 on the display.
Then we can take the cos to get 1
Then we can do b to get \(\sqrt{\frac12}\)
Then we can do b to get \(\sqrt{\frac23}\)
Then we can do c to get \(\sqrt{\frac13}\)
Then we can do b to get \(\sqrt{\frac34}\)
Then we can do c to get \(\sqrt{\frac14}\)
Then we can do b to get \(\sqrt{\frac45}\)
Then we can do b to get \(\sqrt{\frac59}\)
Then we can do a to get \(\frac{3}{\sqrt5}\)
Check: https://www.wolframalpha.com/input/?i=cot(arctan(cos(arctan(cos(arctan(. . .