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Find the shortest distance between the l...

Find the shortest distance between the lines
`(x)/2=(y-2)/3=(z-4)/3 and (x-1)/3=(y-2)/7=(z-3)/8`

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To find the shortest distance between the two lines given by the equations 1. \(\frac{x}{2} = \frac{y-2}{3} = \frac{z-4}{3}\) 2. \(\frac{x-1}{3} = \frac{y-2}{7} = \frac{z-3}{8}\) we will follow these steps: ### Step 1: Write the parametric equations of the lines For the first line, we can express it in vector form as: \[ \mathbf{r_1} = \begin{pmatrix} 0 \\ 2 \\ 4 \end{pmatrix} + \lambda \begin{pmatrix} 2 \\ 3 \\ 3 \end{pmatrix} \] where \(\lambda\) is a parameter. For the second line, we can express it as: \[ \mathbf{r_2} = \begin{pmatrix} 1 \\ 2 \\ 3 \end{pmatrix} + \mu \begin{pmatrix} 3 \\ 7 \\ 8 \end{pmatrix} \] where \(\mu\) is another parameter. ### Step 2: Identify direction vectors and points on the lines From the equations, we identify: - For Line 1: - Point \(A_1 = (0, 2, 4)\) - Direction vector \(\mathbf{b_1} = \begin{pmatrix} 2 \\ 3 \\ 3 \end{pmatrix}\) - For Line 2: - Point \(A_2 = (1, 2, 3)\) - Direction vector \(\mathbf{b_2} = \begin{pmatrix} 3 \\ 7 \\ 8 \end{pmatrix}\) ### Step 3: Compute the cross product of the direction vectors We need to compute \(\mathbf{b_1} \times \mathbf{b_2}\): \[ \mathbf{b_1} \times \mathbf{b_2} = \begin{vmatrix} \mathbf{i} & \mathbf{j} & \mathbf{k} \\ 2 & 3 & 3 \\ 3 & 7 & 8 \end{vmatrix} \] Calculating the determinant: \[ = \mathbf{i}(3 \cdot 8 - 3 \cdot 7) - \mathbf{j}(2 \cdot 8 - 3 \cdot 3) + \mathbf{k}(2 \cdot 7 - 3 \cdot 3) \] \[ = \mathbf{i}(24 - 21) - \mathbf{j}(16 - 9) + \mathbf{k}(14 - 9) \] \[ = 3\mathbf{i} - 7\mathbf{j} + 5\mathbf{k} \] ### Step 4: Find the magnitude of the cross product The magnitude of \(\mathbf{b_1} \times \mathbf{b_2}\) is: \[ |\mathbf{b_1} \times \mathbf{b_2}| = \sqrt{3^2 + (-7)^2 + 5^2} = \sqrt{9 + 49 + 25} = \sqrt{83} \] ### Step 5: Compute the vector \(A_2 - A_1\) Now, we compute the vector from point \(A_1\) to point \(A_2\): \[ \mathbf{A_2 - A_1} = \begin{pmatrix} 1 \\ 2 \\ 3 \end{pmatrix} - \begin{pmatrix} 0 \\ 2 \\ 4 \end{pmatrix} = \begin{pmatrix} 1 \\ 0 \\ -1 \end{pmatrix} \] ### Step 6: Compute the dot product Next, we compute the dot product: \[ (\mathbf{A_2 - A_1}) \cdot (\mathbf{b_1} \times \mathbf{b_2}) = \begin{pmatrix} 1 \\ 0 \\ -1 \end{pmatrix} \cdot \begin{pmatrix} 3 \\ -7 \\ 5 \end{pmatrix} = 1 \cdot 3 + 0 \cdot (-7) + (-1) \cdot 5 = 3 - 5 = -2 \] ### Step 7: Calculate the shortest distance Finally, we can use the formula for the shortest distance \(d\) between the two lines: \[ d = \frac{|(\mathbf{A_2 - A_1}) \cdot (\mathbf{b_1} \times \mathbf{b_2})|}{|\mathbf{b_1} \times \mathbf{b_2}|} \] Substituting the values we found: \[ d = \frac{|-2|}{\sqrt{83}} = \frac{2}{\sqrt{83}} \] ### Final Answer Thus, the shortest distance between the two lines is: \[ \frac{2}{\sqrt{83}} \text{ units} \]
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