Porisma

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Practise five conversions between vector and Cartesian forms

Self-Practice 7:

(a) Convert r=(2,3,−1)+λ(3,4,5)\mathbf r=(2,3,-1)+\lambda(3,4,5), λ real, to Cartesian form.

(b) Convert r=i+j+λ(i+5k)\mathbf r=\mathbf i+\mathbf j+\lambda(\mathbf i+5\mathbf k), λ real, to Cartesian form.

(c) Convert (x−1)/2=y/3=z−4(x-1)/2=y/3=z-4 to a vector equation.

(d) Convert (1−x)/3=(2y−1)/5(1-x)/3=(2y-1)/5, z=4, to a vector equation.

(e) Give vector and Cartesian equations for the line through A with position vector a=i−3j+2k\mathbf a=\mathbf i-3\mathbf j+2\mathbf k, parallel to m=5i+4j−k\mathbf m=5\mathbf i+4\mathbf j-\mathbf k.

CJC · Lecture · Self-Practice 7

Choose a point on the line and a nonzero direction; keep one parameter consistent across all components.

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