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Metamath Proof Explorer

Theorem coshalfpi

Description: The cosine of _pi / 2 is 0. (Contributed by Paul Chapman, 23-Jan-2008)

		Ref	Expression
	Assertion	coshalfpi	$⊢ \cos (\frac{π}{2}) = 0$

Step	Hyp	Ref	Expression
1		sinhalfpilem	$⊢ (\sin (\frac{π}{2}) = 1 \land \cos (\frac{π}{2}) = 0)$
2	1	simpri	$⊢ \cos (\frac{π}{2}) = 0$