Nonlinear functions

Brian Hall
7 min read
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Study Guide Overview
This guide covers nonlinear functions for the AP SAT (Digital) Math exam, focusing on exponential functions (growth/decay, real-world applications), quadratic functions (graph characteristics, solving equations, discriminant), polynomial functions (properties, end behavior, zeros), and rational functions (characteristics, asymptotes, solving equations). It includes example problems and emphasizes key formulas and concepts.
#๐ AP SAT (Digital) Math: Nonlinear Functions - Your Night-Before Guide ๐
Hey there! Feeling the pre-exam jitters? No sweat! This guide is your express ticket to mastering nonlinear functions. We'll break down everything you need to know, focusing on what's most likely to show up on the test. Let's make sure you're feeling confident and ready to crush it! ๐ช
#๐ Exponential Functions
# Basic Structure and Properties
- General Form:
f(x) = a โ bหฃ
a
= initial valueb
= base (growth factor)
- Key Feature: The graph never crosses the x-axis. ๐ซ
- Y-intercept: Always equals the initial value
a
. ๐ - Rate of Change: Constant percent change over equal intervals. ๐
Remember: "a" is where we are, and "b" is how we grow!
# Growth and Decay Behavior
- Growth:
b > 1
(function increases rapidly). ๐ - Decay:
0 < b < 1
(function approaches zero asymptotically). ๐

Exponential growth (left) and decay (right) graphs. Note how growth increases rapidly, while decay approaches zero.
#๐ฐ Exponential Growth and Decay
# Modeling Real-World Scenarios
- Equations:
A(t) = Aโ โ (1 + r)แต
A(t) = Aโ โ eสณแต
Aโ
= initial amountr
= growth/decay ratet
= time
- Doubling Time/Half-Life:
t = ln(2) / ln(1 + r)
- Applications: Population growth, radioactive decay, compound interest. ๐
# Financial Applications
- Continuously Compounded Interest:
A(t) = P โ eสณแต
P
= principal amountr
= annual interest ratet
= time in years
- Use: Financial planning, investments, loans. ๐ฆ
Remember the 'PERT' formula A = Peสณแต
for continuous growth! It's a common application on the exam. ๐ก
#๐งฎ Key Features of Quadratic Graphs
# Parabola Characteristics
- General Form:
f(x) = axยฒ + bx + c
, wherea โ 0
- Graph: A parabola (U-shaped curve). -...

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