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Calculus of Vector-Valued Functions of One Variable

Differentiating and integrating componentwise to obtain velocity and acceleration, including projectile motion under gravity alone.

Active Calculus Multivariable, Calculus of Vector-Valued Functions of One Variable

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4 exercises

Activity 10.3.2

For each of the following vector-valued functions, state any values of aa for which lim⁡t→ar⃗(t)\displaystyle\lim_{t\to a}\vr(t) will not exist and find r⃗ ′(t)\vr\, '(t).

  1. r⃗(t)=⟨cos⁡(t),tsin⁡(t),ln⁡(t)⟩\vr(t) = \langle \cos(t), t\sin(t), \ln(t) \rangle.

  2. r⃗(t)=⟨t2+3t,e−2t,tt2+1⟩\vr(t) = \langle t^2 + 3t, e^{-2t}, \displaystyle\frac{t}{t^2 + 1} \rangle.

  3. r⃗(t)=⟨tan⁡(t),cos⁡(t2),te−t⟩\vr(t) = \langle \tan(t), \cos(t^2), te^{-t} \rangle.

  4. r⃗(t)=⟨t4+4,2t2+t,e2tsin⁡(−2t)⟩\vr(t) = \left\langle \sqrt{t^4 + 4}, \frac{2}{t^2+t} , e^{2t} \sin(-2t) \right\rangle.

2.5

Exercise 35

Compute the derivative of each of the following functions in two different ways: (1) use the rules provided in the theorem stated just after Activity, and (2) rewrite each given function so that it is stated as a single function (either a scalar function or a vector-valued function with three components), and differentiate component-wise. Compare your answers to ensure that they are the same.

  1. r⃗(t)=sin⁡(t)⟨2t,t2,arctan⁡(t)⟩\vr(t) = \sin(t) \langle 2t, t^2, \arctan(t) \rangle

  2. s⃗(t)=r⃗(2t)\vs(t) = \vr(2^t), w…

2.5

Exercise 37

Consider the two vector-valued functions given by and

  1. Determine the point of intersection of the curves generated by r⃗(t)\vr(t) and w⃗(s)\vw(s). To do so, you will have to find values of aa and bb that result in r⃗(a)\vr(a) and w⃗(b)\vw(b) being the same vector.

  2. Use the value of aa you determined in (a) to find a vector form of the tangent line to r⃗(t)\vr(t) at the point where t=at = a.

  3. Use the value of bb you determined in (a) to find a vector form of the…

2.5

Exercise 38

For each given function r⃗\vr, determine ∫r⃗(t) dt\int \vr(t) \ dt. In addition, recalling the Fundamental Theorem of Calculus for functions of a single variable, also evaluate ∫01r⃗(t) dt\int_0^1 \vr(t) \ dt for each given function r⃗\vr. For each of your calculations, you should write a sentence that states whether your result is a vector or a scalar and describes what is being measured.

  1. r⃗(t)=⟨cos⁡(t),1t+1,tet⟩\vr(t) = \left\langle \cos(t), \frac{1}{t+1}, te^t \right\rangle

  2. r⃗(t)=⟨cos⁡(3t),sin⁡(2t),t⟩\vr(t) = \left\langle \cos(3t), \sin(2t), t \right\rangle

  3. r⃗(t)=⟨t1+t2,tet2,11+t2⟩\vr(t) = \left\langle \frac{t}{1+t^2}, te^{t^2}, \frac{1}{1+t^2} \right\rangle

2.5

Adapted from Active Calculus Multivariable © 2013–2026 Nicholas Long, Mitchel T. Keller, and Steven Schlicker. Licensed under CC BY-SA 4.0. Source: Active Calculus Multivariable. Imported at revision 692c03c.