IEEEs, HW help please with complex frequencies??

[Techie333]

I don't understand how to get complex frequencies from real time functions.
For example, in an example they ask to identify all the complex frequencies in the following fuctions:
a) 2e^(-100t)+e^(-200t)sin2000t. The answer is -100+j2000, -100-j2000, -200+j2000, -200-j200.

b) (e^(-10t))cos10tsin40t. The answer is: -10+j30, -10-j30, -10+j50, -10-j50

How do they get these!??!

 

[Techie333]

Wow! That died fast!

 

[Chaotic42]

Originally posted by: Techie333
Wow! That died fast!

It's Saturday. No one wants to think about that.

 

[Techie333]

Originally posted by: Chaotic42

Originally posted by: Techie333
Wow! That died fast!

It's Saturday. No one wants to think about that.

 

[z0mb13]

yeah dude do ur hw on sunday night..

sat night are for parrrtttiessss!!!!

 

[Goosemaster]

Originally posted by: Techie333

Originally posted by: Chaotic42

Originally posted by: Techie333
Wow! That died fast!

It's Saturday. No one wants to think about that.

So you wannna come to my place?

I have some Rod Stewart on and some wheat thins in the closet...

we could have ourselves a hit and steamy little evening...


you in?

 

[PottedMeat]

damn its been a long time but for a start did you try breaking the sin and cos into their exponentials like sin x = e^jwt + e^-jwt ( yeah thats probably wrong ) but then expanding that out? after that i have no idea