Cos Difference identity (cos(A-B)=cos Acos B+sin Asin B)

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cos(A-B)=cos Acos B+sin Asin B

What each symbol means

SymbolWhat it stands for
A, B, x, a, bAs in standard NCERT treatment; domain restrictions apply for tan.

When to use this

Standard NCERT conditions; tan identities exclude odd multiples of π/2 where undefined.