# "Give any three of the criteria that go into selecting the range."

• Jul 21st 2010, 11:41 AM
wiseguy
"Give any three of the criteria that go into selecting the range."
A two part question:

1.) Give the range of $y = cos^{-1}x.$(My answer: All real numbers)
2.) Give any 3 of the criteria that go into selecting the range.

I was under the impression that all there was to the range was maximum y-value minus minimum y value... so how can there be two or more criteria that go into selecting the range?
• Jul 21st 2010, 12:56 PM
skeeter
Quote:

Originally Posted by wiseguy
A two part question:

1.) Give the range of y = cos-1x. (My answer: All real numbers)
2.) Give any 3 of the criteria that go into selecting the range.

I was under the impression that all there was to the range was maximum y-value minus minimum y value... so how can there be two or more criteria that go into selecting the range?

$y = \cos^{-1}(x)$

domain is $[-1,1]$

range is $[0,\pi]$

this should be in your textbook, along with a graph of the inverse cosine function.
• Jul 21st 2010, 01:03 PM
wiseguy
Okay, so listing 1.) look at the graph 2.) reference to the table of values or 3.) look at the trigometric function and its amplitude, and calculate the range (ex. $f(x)=3cosx [-3,3]$)
• Jul 21st 2010, 07:15 PM
wiseguy
I was also wondering, if judging from whether it is an arcsin/arccos vs a sin/cos would qualify as one example. Would love to be able to have unique examples for class tomorrow! :D