How do we check continuity and differentiability of a function defined parametrically e.g. $$x=2t-|t-1|$$ and $$y=2t^2+t|t|$$
2 Answers
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I prefer to consider it as a vector function $$r(t)=x(t)\vec{i}+y(t)\vec{j}$$ in $\mathbb{R}^2 $.
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$t\longmapsto (x_1(t),...,x_n(t))$ is continuous and differntiable $\iff$ $t\longmapsto x_i(t)$ is continuous and differentiable for all $i$.