Coprimes Confusion

If $a\div b=1$ , then can we say that a and b are coprimes. Can a number be coprime to itself ? I got confused due to the text in this question - https://brilliant.org/practice/right-triangle-trigonometry/?p=3

Easy Math Editor

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`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
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Comments

If gcd(a,b)=1, then a and b are coprime integers. In the case of a = b, gcd(a,a)=a which does not follow the definition. Hence, a number cannot be coprime to itself. (Based on my opinion)

Marc Vince Casimiro - 6 years, 3 months ago

You can lookup co prime numbers on Wikipedia but for that question , they mean that if the answer comes out to be 4/16 , you'll have to enter it as 1/4

A Former Brilliant Member - 6 years, 3 months ago

Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$