Product sum difference is a set of identities of trigonometric function in elementary mathematics. It can be proved by means of the sum difference identity of the expansion angle.
sinαsinβ=-1/2[cos(α+β)-cos(α-β)]
cosαcosβ=1/2[cos(α+β)+cos(α-β)]
sinαcosβ=1/2[sin(α+β)+sin(α-β)]
cosαsinβ=1/2[sin(α+β)-sin(α-β)]
Angle u: 30
Angle v: 60
Click "sinusinv" to output the result
Result: sin(30)sin(60) = 0.433013
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