(Basics of Linearity)
(Basics of Linearity)
Line 15: Line 15:
  
 
cos(2t) = <math>\frac{e^{2tj}+e^{-2tj}}{2}</math>
 
cos(2t) = <math>\frac{e^{2tj}+e^{-2tj}}{2}</math>
= <math>\frac{1}{2}*(x1(t) + x2(t))</math>  
+
= <math>\frac{1}{2}*(x1(t) + x2(t))</math>  
 
= <math>\frac{1}{2}*x1(t) + \frac{1}{2}*x2(t))</math>
 
= <math>\frac{1}{2}*x1(t) + \frac{1}{2}*x2(t))</math>

Revision as of 07:19, 18 September 2008

Basics of Linearity

Definition of Linearity: For any constants a and b (that are complext numbers), and inputs x1(t) and x2(t) which yield outputs y1(t) and y2(t),

$ a * x1(t) + b * x2(t) ---> Sys ---> a * y1(t) + b * y2(t) $

We are given a linear system that behaves as follows,

$ e^{2jt} --> Sys --> t*e^{-2jt} $

and asked to find the response to find the response to cos(2t).


Solution: Using the properties of cosine we can convert cos(2t) to an exponential function.

cos(2t) = $ \frac{e^{2tj}+e^{-2tj}}{2} $ = $ \frac{1}{2}*(x1(t) + x2(t)) $ = $ \frac{1}{2}*x1(t) + \frac{1}{2}*x2(t)) $

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