Question

The sound produced by touching each button on a touch-tone phone is described by y = sin 2πlt + sin 2πht where l and h are the low and high frequencies (cycles per seconD. in the figure shown.

Answer 1

Use a calculator to find the graph of the sound emitted by touching the 4 key in a [0, 0.01, 0.001] by [-2, 2, 1] viewing rectangle.

Answer 2

@jim_thompson5910 @lgbasallote

Answer 3

what topic is this?

Answer 4

analytic trig

Answer 5

I'm guessing that the high frequencies are shown at the bottom and the low frequencies are shown off to the right?

Answer 6

if so, then the button "4" has a low frequency of 770 cycles/sec and a high frequency of 1209 cycles/sec

Answer 7

yes but how do u determine which graph it is?

Answer 8

one sec

Answer 9

ok

Answer 10

do you have a graphing calculator?

Answer 11

yes @jim_thompson5910

Answer 12

I graphed the function

y = sin(2*pi*770*x) + sin(2*pi*1209*x)

using a graphing calculator

by typing this in

Answer 13

doing that gives the graph of

Answer 14

so right away, I can rule out choices 1 and 3 since they start too low

Answer 15

so it's a tossup between choices 2 and 4

Answer 16

its 4 right?

Answer 17

yes it is

Answer 18

thank u soo much!

Answer 19

Notice how the first peak and the second peak compare. The first is slightly larger

Answer 20

yes

Answer 21

but in choice 2, the peak 1 is smaller than peak 2

Answer 22

alright, I'm glad you spotted this