ctg(n+2)

ctg(n+2) means cotangent of (n+2). Here are a few useful forms:

• Basic form: ctg(n+2) = cos(n+2) / sin(n+2) (in radians by default).
• Using the cot addition formula: ctg(n+2) = (ctg n · ctg 2 − 1) / (ctg n + ctg 2). This expresses it in terms of ctg n and ctg 2.
• Domain note: sin(n+2) ≠ 0, i.e., n+2 ≠ kπ for any integer k (so n ≠ kπ − 2). If n is an integer, this only matters if n+2 happens to equal an integer multiple of π, which typically doesn’t occur since π is irrational.

If you’re after a specific task (evaluate for a given n, sum a series involving ctg(n+2), telescope a expression, etc.), tell me the exact goal and whether you’re using radians or degrees. Quick example for n = 0: ctg(2) ≈ cos(2)/sin(2) ≈ -0.4577.