# Why is there no amplitude for sec or tan?

• Apr 7th 2013, 06:25 PM
boltage619
Why is there no amplitude for sec or tan?
Hello, for y = sec(3x) , My professor posted that there is no amplitude for this function and i was wondering how she got 2pi/3 as the period?

Also, for y = 3tan(4x-pi/3) , My professor also said that there is no amplitude for this function and i was also wondering how she got pi/4 as the period?
• Apr 7th 2013, 06:34 PM
topsquark
Re: Why is there no amplitude for sec or tan?
Quote:

Originally Posted by boltage619
Hello, for y = sec(3x) , My professor posted that there is no amplitude for this function and i was wondering how she got 2pi/3 as the period?

Also, for y = 3tan(4x-pi/3) , My professor also said that there is no amplitude for this function and i was also wondering how she got pi/4 as the period?

For both I don't agree with how this way said. True, the secant and tangent functions already have a range of -infinity to infinity, but I have a hard time calling that 3 in front of the tangent as anything other than an amplitude. (There is technically a multiplicative factor of "1" in front of the secant as well.) I suspect there is no standard term for the 3, except maybe a "dilation."

For the periods let's take the secant function first. Assume a value of X such that the function starts to repeat itself. The secant function repeats itself every 2*pi radians. Thus 3X = 2*pi. etc.

The tangent is a bit trickier, but the same method applies. tangent repeats itself every pi radians. (If this seems odd, graph it.)

-Dan