App description

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)]

Usage example

Angle u: 30

Angle v: 60

Click "sinusinv" to output the result

Result: sin(30)sin(60) = 0.433013