Product to Sum Identities Formula

Equation for calculate product to sum identities is,

Product to Sum Equations:
sin(θ).sin(φ) = [cos((θ)-(φ)) - cos((θ)+(φ))] / 2
cos(θ).cos(φ) = [cos((θ)-(φ)) + cos((θ)+(φ))] / 2
sin(θ).cos(φ) = [sin((θ)+(φ)) + sin((θ)-(φ))] / 2
cos(θ).sin(φ) = [sin((θ)+(φ)) - sin((θ)-(φ))] / 2
tan(θ).tan(φ) = [cos((θ)-(φ)) - cos((θ)+(φ))] / [cos((θ)-(φ)) + cos((θ)+(φ))]