$$\lim_{t \to 0^-} \log{\left(t^{2} + 1 \right)} = 0$$ More at t→0 from the left $$\lim_{t \to 0^+} \log{\left(t^{2} + 1 \right)} = 0$$ $$\lim_{t \to \infty} \log{\left(t^{2} + 1 \right)} = \infty$$ More at t→oo $$\lim_{t \to 1^-} \log{\left(t^{2} + 1 \right)} = \log{\left(2 \right)}$$ More at t→1 from the left $$\lim_{t \to 1^+} \log{\left(t^{2} + 1 \right)} = \log{\left(2 \right)}$$ More at t→1 from the right $$\lim_{t \to -\infty} \log{\left(t^{2} + 1 \right)} = \infty$$ More at t→-oo