I need help with these two trig problems!!

Question

1) graph the sinusoidal function y=-3sin(1/3x) 2) graph the function y=5cos(-2x+pi/2)? 

 

 

Answer 1

(1)

The Function is y = -3sin((1/3)x).

This is in the form of y = Asin(Bx+C)

Amplitude of the Function is A = -3

Period of the Function is 2π/B = 2π/(1/3) = 6π.

Phase Shift is C/B = 0/(1/3) = 0.

Graph the function between x = 0 and x = 9π

Find the Points of the Graph

x	0	3π/2	3π	9π/2	6π	15π/2	9π
y	0	-3	0	3	0	-3	0

Graph

Answer 2

(2)

The Function is y = 5cos(-2x+π/2).

y = 5cos(2x-π/2)                    (Since cos(-x) = cosx)

This is in the form of y = Acos(Bx-C)

Amplitude of the Function is A = 5

Period of the Function is 2π/B = 2π/2 = π.

Phase Shift is C/B = (π/2)/(2) = π/4.

Graph the function between x = 0 and x = 3π/2

Find the Points of the Graph in the interval of π/4

x	0	π/4	π/2	3π/4	π	5π/4	3π/2
y	0	5	0	-5	0	5	0

Graph