Compute lim x→3 (x² − 9) / (x − 3)

💡 Factor numerator.

Is f(x) = |x| differentiable at x = 0?

💡 Check left and right derivatives.

Does the sequence aₙ = 1/n converge? If yes, to what?

💡 As n → ∞, what does 1/n approach?