Precalculus: periodic and reciprocal graph evidence
Construct complete periodic graphs, compare finite rates and fit competing sinusoidal periods using new evidence. School algebra, unit-circle coordinates and graph reading suffice; calculus is not required.
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Readiness and preparation
Check your starting point
Try these short questions on paper, then compare your reasoning. They are optional self-checks, not a placement score or a navigation requirement. Use a targeted review when useful and return with your browser’s Back control.
How do a sinusoid’s period and amplitude differ?
Horizontal repetition and vertical variation describe different features.
Compare reasoning and find a refresher
The period is the smallest positive input shift that repeats a nonconstant sinusoid. Its amplitude is half the difference between its maximum and minimum outputs. Their units follow the input and output respectively.
A graph must retain exclusions and separate branches.
Compare reasoning and find a refresher
Check its original denominator: tangent and secant require nonzero cosine; cotangent and cosecant require nonzero sine. A plotting line must never join branches across an excluded input.