# 條件命題

There are infinitely many prime numbers.

$$P$$ is sufficient for $$Q$$, and $$Q$$ is necessary for $$P$$.

If $$f(a)=0$$ for a number $$a$$, then $$a$$ is said to be a solution of the equation $$f(x)=0$$.

「若且惟若」在中國大陸稱為「當且僅當」。

 [語音講解：conditional.mp3]

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Created: Aug 12, 2022
Last Revised: 12/01