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