Porisma

A hint to get started

Distinguish an absolute input from the order of affine transformations

(a) The supplied graph y=f(x)y=f(x) has asymptotes y=0, y=2, x=−1, x=1, maximum (3,3), minimum at O and the right zero (2,0) shown. Sketch:

(i) y=f(∣1+x∣)y=f(|1+x|); marks

(ii) y=1/f(x)y=1/f(x). marks

(b) Alfred and Betty are to transform y=f(x)y=f(x) to y=5f(2x+1)−3y=5f(2x+1)-3, with original f(x)=x2f(x)=x^2 and target y=5(2x+1)2−3y=5(2x+1)^2-3.

Alfred’s steps, in order: 1.Scale parallel to y by 5; 2.Translate down 3; 3. Scale parallel to x by 1/2; 4. Translate along x by −1.

Betty’s steps, in order: 1.Translate along x by −1; 2. Scale parallel to x by 1/2; 3. Scale parallel to y by 5; 4. Translate down 3.

One person made an error in one step.

(i) Identify the person and incorrect step. marks

(ii) Give the final equation resulting from that incorrect sequence. mark

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Source graph with asymptotes x=-1,x=1, left horizontal y=0 and right horizontal y=2, minimum O(0,0), maximum (3,3) and right zero (2,0). Independent qualitative interpolation, not an exact supplied formula.
Source graph with asymptotes x=-1,x=1, left horizontal y=0 and right horizontal y=2, minimum O(0,0), maximum (3,3) and right zero (2,0). Independent qualitative interpolation, not an exact supplied formula.
Source graph with asymptotes x=-1,x=1, left horizontal y=0 and right horizontal y=2, minimum O(0,0), maximum (3,3) and right zero (2,0). Independent qualitative interpolation, not an exact supplied formula.

[2012/SAJC/Promo/10]

CJC · Review problems · Question 8

Keep the absolute-value bars around the whole input 1+x, then evaluate the original f only at nonnegative arguments.

Read the worked solution