Porisma

A hint to get started

Transform a plane after finding intersections and parallel offsets

A has position vector −i−11j+2k-\mathbf i-11\mathbf j+2\mathbf k. Line l is (x−9)/7=y+3=−(z+1)/2(x-9)/7=y+3=-(z+1)/2, and plane p is 5x+3y+bz+1=05x+3y+bz+1=0.

(i) If l and p meet in exactly one point, what can be said about b? marks

Use b=1 for the rest.

(ii) Find N, their intersection. marks

(iii) Show the shortest distance from A to p is 35\sqrt{35}. marks

(iv) Plane p1 is parallel to p at shortest distance 2352\sqrt{35}. Find a possible equation in scalar-product form. marks

(v) Plane p undergoes, in order: translation 3 units in negative x; scaling parallel to the y-axis by factor 1/2; reflection in the xy-plane. Find a Cartesian equation of the resulting p2. marks

[2016/CJC/Promo/12]

CJC · Review problems · Question 8

Apply transformations to point coordinates, then substitute the inverse map into the plane equation.

Read the worked solution