# Homework Help: Signals and Systems [Calc the Fundamental Period]

1. Apr 14, 2010

### damasgate

1. The problem statement, all variables and given/known data
Determine the Fundamental Period and Frequency

I got this question wrong on My midterm and I was wondering if you guys could give me some feedback on it

x(t) = cos[50(pi)t] + sin[15(pi)t]

2. Relevant equations

T(fundamental Period) = 2(pi)/w // w is the frequency

3. The attempt at a solution
I tried finding the peirod of both sine and cosine

for first T = 2(pi)/50(pi) = 1/25
for second T=2(pi)/15(pi) = 2/15

then you have to find the least common Multiple(I think this is where I messed it up)

I got for (1/25) and (2/15) LCM to be 1/75 [ like I said I think this is wrong, I'm not sure how to do LCM with fractions]

I got T=1/75 (fundamental Period)
then I got W=2(pi)/T = 150(pi0
and then I got TWO big Xs on them :(
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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