What is the amplitude and period of #y=2sinx#?

2 Answers
Feb 15, 2018

#2,2pi#

Explanation:

#"the standard form of the "color(blue)"sine function"# is.

#color(red)(bar(ul(|color(white)(2/2)color(black)(y=asin(bx+c)+d)color(white)(2/2)|)))#

#"where amplitude "=|a|," period "=(2pi)/b#

#"phase shift "=-c/b" and vertical shift "=d#

#"here "a=2,b=1,c=d=0#

#rArr"amplitude "=|2|=2," period "=2pi#

Feb 15, 2018

amplitude: #2#
period: #360^@#

Explanation:

the amplitude of #y = sin x# is #1#.

#(sin x)# is multiplied by #2#, i.e. after the function #sin x# has been applied, the result is multiplied by #2#.

the result of #sin x# for the graph #y = sinx# is #y# at any point on the graph.

the result of #2 sin x# for the graph #y = sin x# would be #2y# at any point on the graph.

since #y# is the vertical axis, changing the coefficient of #(sin x)# changes the vertical height of the graph.

the amplitude is the value of the distance between the #x#-axis and the highest or lowest point on the graph.

for #y = (1) sin x#, the amplitude is #1#.

for #y = 2 sin x#, the amplitude is #2#.

the period of a graph is how often the graph repeats itself.

the graph of #y = sin x# will repeat its pattern every #360^@#. #sin 0^@ = sin 360^@ = 1#, #sin 270^@ = sin 630^@ = -1#, etc.

desmos.com/calculator
(the graph shown is #y = sin x# where #0^@<=x<=720^@#)

if the value that the function #sin# is being applied to changes, the graph will change along the #x#-axis.

e.g. if the value is changed to #y = sin 2x#, #y# will be #sin 90^@# at #x = 45^@#, and #sin 360^@# at #x = 180^@#.

the range of the values that #y# can take will stay the same, but they will be at different points of #x#.

if the coefficient of #x# is increased, the highest and lowest points on the graph will seem closer together.

however, the function in question does not the coefficient of #(x)# - only the coefficient of #(sin x)#.

the range of values that #y# can take is doubled, but #x# will repeat itself at the same points.

the amplitude is #2#, and the period is #360^@#.