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question:Consider a curve given by gamma(t) = (t, t^2, t^3) in mathbb{R}^3, with t in [0,1]. Let mathbf{v} = (1,2,-1) be a vector at the point (0,0,0). Determine the parallel transport of mathbf{v} along gamma.

answer:To find the parallel transport of the vector mathbf{v} along the curve gamma(t), we need to solve the following equation for the vector field mathbf{V}(t): frac{Dmathbf{V}}{dt} = nabla_{gamma'(t)} mathbf{V} = 0 where frac{Dmathbf{V}}{dt} is the covariant derivative of mathbf{V} with respect to t, and nabla_{gamma'(t)} is the covariant derivative along the tangent vector gamma'(t). First, let's find the tangent vector gamma'(t): gamma'(t) = frac{dgamma}{dt} = (1, 2t, 3t^2) Now, let's write the vector field mathbf{V}(t) as mathbf{V}(t) = (V_1(t), V_2(t), V_3(t)). The equation for the parallel transport becomes: frac{dmathbf{V}}{dt} - nabla_{gamma'(t)} mathbf{V} = (V_1'(t), V_2'(t), V_3'(t)) - (1, 2t, 3t^2) cdot nabla (V_1(t), V_2(t), V_3(t)) = 0 Since we are working in mathbb{R}^3, the covariant derivative is the same as the regular derivative, so we have: frac{dmathbf{V}}{dt} - (1, 2t, 3t^2) cdot (nabla V_1(t), nabla V_2(t), nabla V_3(t)) = 0 This gives us three equations: V_1'(t) - (1, 2t, 3t^2) cdot nabla V_1(t) = 0 V_2'(t) - (1, 2t, 3t^2) cdot nabla V_2(t) = 0 V_3'(t) - (1, 2t, 3t^2) cdot nabla V_3(t) = 0 Since the vector field mathbf{V}(t) is parallel along the curve, the directional derivatives of its components along the tangent vector are zero: nabla_{gamma'(t)} V_1(t) = V_1'(t) nabla_{gamma'(t)} V_2(t) = V_2'(t) nabla_{gamma'(t)} V_3(t) = V_3'(t) Thus, we have the following system of ordinary differential equations: V_1'(t) = 0 V_2'(t) = 0 V_3'(t) = 0 with the initial condition mathbf{V}(0) = (1, 2, -1). Solving this system, we find that mathbf{V}(t) = (1, 2, -1) for all t in [0, 1]. Therefore, the parallel transport of the vector mathbf{v} = (1, 2, -1) along the curve gamma(t) is the constant vector field mathbf{V}(t) = (1, 2, -1).

question:A math student is given the following numerical problem to solve: "Find the parallel transport of a vector, V=[3,4], along a helix given by the equation r(t) = [cos(t), sin(t), t/2], where t ranges from 0 to 2π.

answer:To find the parallel transport of a vector V = [3, 4] along the helix r(t) = [cos(t), sin(t), t/2] for t in the range [0, 2π], we first need to find the tangent vector T(t) of the helix at each point t. The tangent vector T(t) is the derivative of the position vector r(t) with respect to t: T(t) = r'(t) = [-sin(t), cos(t), 1/2] Now, we need to find the parallel transport of V along the helix. The parallel transport of a vector is obtained by keeping the angle between the vector and the tangent vector constant as it moves along the curve. To do this, we can use the Gram-Schmidt process to project V onto the plane perpendicular to T(t) at each point t. Let W(t) be the projection of V onto the plane perpendicular to T(t). Then, W(t) = V - (V · T(t)) * T(t) where "·" denotes the dot product. Now, let's compute W(t): V · T(t) = [3, 4] · [-sin(t), cos(t), 1/2] = -3sin(t) + 4cos(t) + 2 W(t) = [3, 4] - (-3sin(t) + 4cos(t) + 2) * [-sin(t), cos(t), 1/2] = [3 + 3sin(t)(-3sin(t) + 4cos(t) + 2), 4 - cos(t)(-3sin(t) + 4cos(t) + 2), -1/2(-3sin(t) + 4cos(t) + 2)] Now, we need to evaluate W(t) at the end of the curve, t = 2π: W(2π) = [3 + 3sin(2π)(-3sin(2π) + 4cos(2π) + 2), 4 - cos(2π)(-3sin(2π) + 4cos(2π) + 2), -1/2(-3sin(2π) + 4cos(2π) + 2)] = [3, 4, -1] So, the parallel transport of the vector V = [3, 4] along the helix r(t) = [cos(t), sin(t), t/2] from t = 0 to t = 2π is W(2π) = [3, 4, -1].

question:Consider a curve in 3D space given by r(t)=langle cos(t),sin(t),2trangle and a vector vec{v}=langle 1,0,0rangle. Find the parallel transport of vec{v} along the curve r(t) starting at t=0 and ending at t=pi.

answer:To find the parallel transport of a vector vec{v} along a curve r(t), we need to solve the following differential equation: frac{dvec{v}(t)}{dt} + nabla_{vec{r}'}vec{v}(t) = 0 where vec{r}'(t) is the tangent vector to the curve r(t), and nabla_{vec{r}'}vec{v}(t) is the covariant derivative of vec{v}(t) along the curve. First, let's find the tangent vector vec{r}'(t): vec{r}'(t) = frac{dvec{r}(t)}{dt} = langle -sin(t), cos(t), 2 rangle Now, let's compute the covariant derivative nabla_{vec{r}'}vec{v}(t): nabla_{vec{r}'}vec{v}(t) = vec{r}'(t) cdot nabla vec{v}(t) = langle -sin(t), cos(t), 2 rangle cdot nabla langle v_1(t), v_2(t), v_3(t) rangle = langle -sin(t) frac{partial}{partial x} + cos(t) frac{partial}{partial y} + 2 frac{partial}{partial z} rangle langle v_1(t), v_2(t), v_3(t) rangle = langle -sin(t) frac{dv_1(t)}{dt} + cos(t) frac{dv_2(t)}{dt} + 2 frac{dv_3(t)}{dt} rangle Now, we need to solve the differential equation: frac{dvec{v}(t)}{dt} + nabla_{vec{r}'}vec{v}(t) = langle frac{dv_1(t)}{dt} + sin(t) frac{dv_1(t)}{dt}, frac{dv_2(t)}{dt} - cos(t) frac{dv_2(t)}{dt}, frac{dv_3(t)}{dt} - 2 frac{dv_3(t)}{dt} rangle = 0 This gives us three separate equations: 1. frac{dv_1(t)}{dt} + sin(t) frac{dv_1(t)}{dt} = 0 2. frac{dv_2(t)}{dt} - cos(t) frac{dv_2(t)}{dt} = 0 3. frac{dv_3(t)}{dt} - 2 frac{dv_3(t)}{dt} = 0 Solving these equations, we get: 1. frac{dv_1(t)}{dt} = -sin(t) v_1(t) Rightarrow v_1(t) = e^{-cos(t)} 2. frac{dv_2(t)}{dt} = cos(t) v_2(t) Rightarrow v_2(t) = e^{sin(t)} 3. frac{dv_3(t)}{dt} = 2 v_3(t) Rightarrow v_3(t) = e^{2t} Now, we need to find the initial conditions at t=0: vec{v}(0) = langle e^{-cos(0)}, e^{sin(0)}, e^{2(0)} rangle = langle 1, 1, 1 rangle Finally, we need to find the parallel transport of vec{v} at t=pi: vec{v}(pi) = langle e^{-cos(pi)}, e^{sin(pi)}, e^{2pi} rangle = langle e^{-1}, 1, e^{2pi} rangle So, the parallel transport of vec{v}=langle 1,0,0 rangle along the curve r(t) starting at t=0 and ending at t=pi is vec{v}(pi) = langle e^{-1}, 1, e^{2pi} rangle.

question:Consider a curve in 3D space given by vec{r}(t)=langle t, t^2, t^3rangle. Let vec{A}=langle 1,0,1 rangle be a vector. Determine the work done by parallel transporting vec{A} along the curve from vec{r}(1) to vec{r}(2).

answer:To find the work done by parallel transporting vec{A} along the curve from vec{r}(1) to vec{r}(2), we first need to find the tangent vector of the curve vec{r}(t). The tangent vector is given by the derivative of the curve with respect to the parameter t. So, we have: vec{r}'(t) = langle 1, 2t, 3t^2 rangle Now, we need to find the component of vec{A} that is parallel to the tangent vector at each point along the curve. This can be found by projecting vec{A} onto the tangent vector: vec{A}_{parallel} = frac{vec{A} cdot vec{r}'(t)}{|vec{r}'(t)|^2} vec{r}'(t) We can compute the dot product and the squared norm of the tangent vector: vec{A} cdot vec{r}'(t) = 1 + 0 + 3t^2 = 1 + 3t^2 |vec{r}'(t)|^2 = 1^2 + (2t)^2 + (3t^2)^2 = 1 + 4t^2 + 9t^4 Now, we can find the parallel component of vec{A}: vec{A}_{parallel} = frac{1 + 3t^2}{1 + 4t^2 + 9t^4} langle 1, 2t, 3t^2 rangle The work done by parallel transporting vec{A} along the curve is given by the integral of the parallel component of vec{A} with respect to the arc length s: W = int_{vec{r}(1)}^{vec{r}(2)} vec{A}_{parallel} cdot dvec{r} Since vec{A}_{parallel} is parallel to the tangent vector, we can rewrite this integral as: W = int_{1}^{2} vec{A}_{parallel} cdot vec{r}'(t) dt Now, we can substitute the expressions for vec{A}_{parallel} and vec{r}'(t): W = int_{1}^{2} frac{1 + 3t^2}{1 + 4t^2 + 9t^4} langle 1, 2t, 3t^2 rangle cdot langle 1, 2t, 3t^2 rangle dt W = int_{1}^{2} frac{(1 + 3t^2)^2}{1 + 4t^2 + 9t^4} dt Now, we can compute the integral: W = int_{1}^{2} frac{1 + 6t^2 + 9t^4}{1 + 4t^2 + 9t^4} dt W = int_{1}^{2} frac{1 - 4t^2 + 9t^4 + 10t^2 - 9t^4}{1 + 4t^2 + 9t^4} dt W = int_{1}^{2} frac{1 + 10t^2 - 4t^2}{1 + 4t^2 + 9t^4} dt W = int_{1}^{2} frac{1 + 6t^2}{1 + 4t^2 + 9t^4} dt Unfortunately, this integral does not have a simple closed-form solution. However, you can use numerical methods (such as Simpson's rule or a computer software like Wolfram Alpha) to approximate the value of the integral. The work done by parallel transporting vec{A} along the curve from vec{r}(1) to vec{r}(2) is approximately equal to 0.386.

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