🧭 CapCompassfree study planner

Nonlinear Functions — Digital SAT SAT Math revision notes

A 3-page visual revision sheet for Nonlinear Functions, written for Digital SAT SAT Math. Formulas, diagrams and the traps that cost marks, laid out to be read the night before rather than the term before. Free, and it opens inside CapCompass.

Nonlinear Functions revision notes, page 1 of 3 Page 1 as PDF
A preview of page 1 — all 3 pages open full size in the app.

Nonlinear Functions in one look

parabolas, exponentials, and what a shift does to an equation

Nonlinear means the rate of change itself changes

  • a linear function adds the same amount every step. A quadratic adds a growing amount, and an exponential multiplies by the same factor every step
  • that one distinction answers most of the modelling questions: added each time is linear, multiplied each time is exponential
  • a quadratic drawn on axes is a parabola, and every parabola has a vertex (its highest or lowest point) and an axis of symmetry through it
  • the graph of a function and its equation carry the same information. The question decides which of the two is quicker to read

One quadratic, three forms

  • standard form, and c is the y-intercept y=ax^2+bx+c
  • vertex form, vertex at (h,k) y=a(x-h)^2+k
  • factored form, x-intercepts at p and q y=a(x-p)(x-q)
  • axis of symmetry, which is also the x of the vertex x=-b/2a
  • sum of the two roots, with no factorising at all p+q=-b/a

Worked: intercepts and vertex

Q. h(x)=x^2-8x+12. What is the sum of the x-intercepts of y=h(x), and where is the vertex?

  1. x-intercepts are the x values with h(x)=0: x^2-8x+12=0
  2. factorise: (x-2)(x-6)=0, so x=2 and x=6
  3. their sum is 8, which is also -b/a=8, so the factorising was optional for this part
  4. the vertex sits on the axis of symmetry, midway between the roots: x=2+6/2=4
  5. substitute back for the height: h(4)=16-32+12=-4

Answer: the intercepts sum to 8, and the vertex is (4,-4)

Page 1 of 3. The full sheet, all 3 pages, opens free in the app.

What this Nonlinear Functions sheet covers

Open the full Nonlinear Functions sheet →Free, works offline, no account needed. All 3 pages, plus a study plan built around your own exam dates.

How CapCompass uses this sheet

These notes are not a standalone PDF. CapCompass plans SAT Math chapter by chapter against your real exam dates and free hours, and when the plan reaches Nonlinear Functions the sheet opens inside the study block itself — at the page covering the sub-topic that block is on, with the timer still running. Revision arrives at the moment the plan says revise, instead of having to be gone looking for.

More SAT Math revision notes