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Day 49: Graphs of Secant and Cosecant. Plan for the Day. Review Homework Secant and Cosecant Homework Next time: Quiz on Graphing Sine and Cosine (including bx – c). x. 0. cos x. 1. 0. -1. 0. 1. y = cos x. y. x. Graph of the Cosine Function. Cosine Function.
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Plan for the Day • Review Homework • Secant and Cosecant • Homework • Next time: Quiz on Graphing Sine and Cosine(including bx – c)
x 0 cos x 1 0 -1 0 1 y = cos x y x Graph of the Cosine Function Cosine Function To sketch the graph of y = cos x first locate the key points.These are the maximum points, the minimum points, and the intercepts. Then, connect the points on the graph with a smooth curve that extends in both directions beyond the five points. A single cycle is called a period.
x 0 sin x 0 1 0 -1 0 y = sin x y x Graph of the Sine Function Sine Function To sketch the graph of y = sin x first locate the key points.These are the maximum points, the minimum points, and the intercepts. Then, connect the points on the graph with a smooth curve that extends in both directions beyond the five points. A single cycle is called a period.
Key Steps in Graphing Sine and Cosine Identify the key points of your basic graph • Find the new period (2π/b) • Find the new beginning (bx - c = 0) • Find the new end (bx - c = 2π) • Find the new interval (new period / 4) to divide the new reference period into 4 equal parts to create new x values for the key points • Adjust the y values of the key points by applying the change in height (a) and the vertical shift (d) • Graph key points and connect the dots
Get out your graphing calculator… Graph the following y = cos x y = sec x What do you see??
The graph y = sec x, use the identity . y Properties of y = sec x 1. domain : all real x x 4. vertical asymptotes: Graph of the Secant Function Secant Function At values of x for which cos x = 0, the secant function is undefined and its graph has vertical asymptotes. 2. range: (–,–1] [1, +) 3. period: 2
First graph: • y = 2cos (2x – π) + 1 Then try: • y = 2sec (2x – π) + 1
Graph Graph the following y = sin x y = csc x What do you see??
To graph y = csc x, use the identity . y Properties of y = csc x 1. domain : all real x x 4. vertical asymptotes: Graph of the Cosecant Function Cosecant Function At values of x for which sin x = 0, the cosecant functionis undefined and its graph has vertical asymptotes. 2. range: (–,–1] [1, +) 3. period: 2 where sine is zero.
First graph: • y = -3 sin (½x + π/2) – 1 Then try: • y = -3 csc (½x + π/2) – 1
Key Steps in Graphing Secant and Cosecant • Identify the key points of your reciprocal graph (sine/cosine), note the original zeros, maximums and minimums • Find the new period (2π/b) • Find the new beginning (bx - c = 0) • Find the new end (bx - c = 2π) • Find the new interval (new period / 4) to divide the new reference period into 4 equal parts to create new x values for the key points • Adjust the y values of the key points by applying the change in height (a) and the vertical shift (d) • Using the original zeros, draw asymptotes, maximums become minimums, minimums become maximums… • Graph key points and connect the dots based upon known shape
Homework 26 • Page 318:14, 26, 16, 27 • Quiz next time