Math Problem Statement

(1 point) Suppose you start at the point (7,3,8) and move 3 units along the curve:

π‘₯(𝑑)=2𝑑+7,𝑦(𝑑)=4𝑑3β€Ύβ€Ύβˆš3+3,𝑧(𝑑)=𝑑22+8

in the positive direction. Where are you now?

Solution

We are given a point (7,3,8)(7, 3, 8) and a parameterized curve described by:

x(t)=2t+7,y(t)=4t3/2+3,z(t)=t22+8x(t) = 2t + 7, \quad y(t) = 4t^{3/2} + 3, \quad z(t) = \frac{t^2}{2} + 8

We need to find where we end up after moving 3 units along the curve in the positive direction.

Step 1: Parametrize the curve.

The velocity vector along the curve is the derivative of the position functions x(t),y(t),z(t)x(t), y(t), z(t) with respect to tt:

v(t)=(dxdt,dydt,dzdt)\mathbf{v}(t) = \left( \frac{dx}{dt}, \frac{dy}{dt}, \frac{dz}{dt} \right)

So, we differentiate each component:

dxdt=2,dydt=6t1/2,dzdt=t\frac{dx}{dt} = 2, \quad \frac{dy}{dt} = 6t^{1/2}, \quad \frac{dz}{dt} = t

Thus, the velocity vector is:

v(t)=⟨2,6t1/2,t⟩\mathbf{v}(t) = \langle 2, 6t^{1/2}, t \rangle

Step 2: Calculate the speed.

The speed is the magnitude of the velocity vector:

βˆ₯v(t)βˆ₯=(2)2+(6t1/2)2+(t)2=4+36t+t2\|\mathbf{v}(t)\| = \sqrt{(2)^2 + (6t^{1/2})^2 + (t)^2} = \sqrt{4 + 36t + t^2}

Step 3: Arc length formula.

The distance traveled along a curve is given by the arc length formula:

s(t)=∫0tβˆ₯v(Ο„)βˆ₯ dΟ„=∫0t4+36Ο„+Ο„2 dΟ„s(t) = \int_0^t \|\mathbf{v}(\tau)\| \, d\tau = \int_0^t \sqrt{4 + 36\tau + \tau^2} \, d\tau

We need to find tt such that the arc length equals 3 units, i.e.,

∫0t4+36Ο„+Ο„2 dΟ„=3\int_0^t \sqrt{4 + 36\tau + \tau^2} \, d\tau = 3

Solving this integral directly can be complex, so let me approximate this numerically to find the value of tt corresponding to 3 units of movement.The value of tt that corresponds to moving 3 units along the curve is approximately tβ‰ˆ0.739t \approx 0.739.

Step 4: Calculate the new position.

Now, using t=0.739t = 0.739, we can find the new position by plugging this value into the parametric equations for x(t),y(t),z(t)x(t), y(t), z(t):

x(0.739)=2(0.739)+7=8.478x(0.739) = 2(0.739) + 7 = 8.478 y(0.739)=4(0.739)3/2+3β‰ˆ4.957y(0.739) = 4(0.739)^{3/2} + 3 \approx 4.957 z(0.739)=(0.739)22+8β‰ˆ8.273z(0.739) = \frac{(0.739)^2}{2} + 8 \approx 8.273

Thus, after moving 3 units along the curve, your new position is approximately:

(8.478,4.957,8.273)(8.478, 4.957, 8.273)

Would you like any further details or explanations?

Here are 5 related questions to expand on this topic:

  1. How can you approximate arc length for curves with complex parameterizations?
  2. How does the velocity vector help in understanding movement along a curve?
  3. What are some techniques for solving integrals involving arc length?
  4. How does curvature of a curve affect arc length?
  5. What other methods can be used to solve this kind of parametric motion problem?

Tip: Numerical methods like integration and root-finding are often used when exact solutions to arc length problems are difficult to obtain.

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Math Problem Analysis

Mathematical Concepts

Parametric Equations
Arc Length
Vector Calculus

Formulas

x(t) = 2t + 7
y(t) = 4t^(3/2) + 3
z(t) = t^2/2 + 8
Velocity Vector v(t) = <dx/dt, dy/dt, dz/dt>
Speed |v(t)| = sqrt((dx/dt)^2 + (dy/dt)^2 + (dz/dt)^2)
Arc Length s(t) = integral(sqrt((dx/dt)^2 + (dy/dt)^2 + (dz/dt)^2) dt)

Theorems

Arc Length Formula
Fundamental Theorem of Calculus

Suitable Grade Level

College Calculus