Check if limx→0f(x)\lim_{x \to 0} f(x)limx→0f(x) exists for f(x)={x−2x<0x+2x≥0f(x) = \begin{cases} x - 2 & x < 0 \\ x + 2 & x \ge 0 \end{cases}f(x)={x−2x+2x<0x≥0.
Evaluate limx→1[x3−x2+1]\lim_{x \to 1} [x^3 - x^2 + 1]limx→1[x3−x2+1].
Analyze lines and planes in three-dimensional space.