Let r(t)=x(t),y(t)|be a vector-valued function defined on an open interval containing the point t0. Prove that r(t) is continuous at t0if and only if x(t)and y(t)are both continuous at t0.

Short Answer

Expert verified

Ans: It is proved that r(t)is continuous at t0if and only ifx(t)andy(t)are continuous att0

Step by step solution

01

Step 1. Given information.

given,

r(t)=x(t),y(t)|

02

Step 2. Consider a vector valued function r(t)=⟨x(t),y(t)⟩ defined on an interval containing t0.

The objective is to prove that r(t) is continuous at t0if and only if x(t) and y(t) are both continuous at t0.

Note: A vector function r(t)is said to be continuous at t0if limtt0x(t)andlimtt0y(t)exists, then use say that x(t) and y(t) are both continuous at t0.

Let limtt0x(t)=xt0and letlimtt0y(t)=yt0

03

Step 3. Consider 

limtt0r(t)=limtt0x(t),y(t)=limtt0x(t)i+limtt0y(t)j=xt0i+yt0j=xt0,yt0=rt0

limtt0r(t)=rt0happens only when role="math" localid="1649614127296" x(t)andy(t)are continuous at t0.

Thus, r(t)is continuous at t0if and only if x(t)andy(t)are continuous at t0.

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