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Fungrim entry: ad6c1c

sin ⁣(a)sin ⁣(b)=cos ⁣(ab)cos ⁣(a+b)2\sin\!\left(a\right) \sin\!\left(b\right) = \frac{\cos\!\left(a - b\right) - \cos\!\left(a + b\right)}{2}
Assumptions:aCandbCa \in \mathbb{C} \,\mathbin{\operatorname{and}}\, b \in \mathbb{C}
\sin\!\left(a\right) \sin\!\left(b\right) = \frac{\cos\!\left(a - b\right) - \cos\!\left(a + b\right)}{2}

a \in \mathbb{C} \,\mathbin{\operatorname{and}}\, b \in \mathbb{C}
Fungrim symbol Notation Short description
Sinsin ⁣(z)\sin\!\left(z\right) Sine
CCC\mathbb{C} Complex numbers
Source code for this entry:
    Formula(Equal(Mul(Sin(a), Sin(b)), Div(Sub(Cos(Sub(a, b)), Cos(Add(a, b))), 2))),
    Variables(a, b),
    Assumptions(And(Element(a, CC), Element(b, CC))))

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2019-08-25 15:30:03.056001 UTC