asinA+bcosA=√(a^2+b^2)sin(A+M)，tanM=sinM/cosM=b/a

Sum and difference product formula of trigonometric function

sinα+sinβ= 2 sin((α+β)/2)cos((α-β)/2)

sinα-sinβ= 2cos((α+β)/2)sin((α-β)/2)

cosα+cosβ= 2cos((α+β)/2)cos((α-β)/2)

cosα-cosβ=-2 sin((α+β)/2)sin((α-β)/2)

Formula of product and difference of trigonometric function

sinαcosβ= 0.5[sin(α+β)+sin(α-β)]

cosαsinβ= 0.5[sin(α+β)-sin(α-β)]

cosαcosβ= 0.5[cos(α+β)+cos(α-β)]

sinαsinβ=-0.5[cos(α+β)-cos(α-β)]