00:01
First thing we need to do is evaluate sine hx over cosine hx.
00:12
And this equals sine hx times 1 over cosine hx.
00:21
This is the same thing as e to the x minus e to the negative x power all over 2 times 2 over e to the x plus e to negative x power.
00:32
These are just definitions that we're using.
00:37
The twos will cancel, and this will become e to the x minus e to the negative x all over e to the x plus e to the negative x.
00:49
If you look at your definitions, this is the same thing as 10hx.
00:55
That must mean this original function is the same thing as tangent.
01:03
Part b, because you know we can never have just one part to this problem.
01:07
And we can have to have lots of parts.
01:10
That makes it fun.
01:13
See what part b is asking, because i don't remember.
01:17
Look it up really fast.
01:19
Okay, so we're testing c.
01:21
It is odd.
01:24
So remember, if for something to be odd, you must plug in negative x, and if you get negative f of x out, it is odd.
01:35
Okay...