Solving Laplace Transform of cos2at | Simple Homework Guide

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SUMMARY

The Laplace Transform of cos(2at) is derived using the formula L[cos(bt)] = s/(s² + b²). The correct application involves recognizing that cos(2at) can be expressed as 1/2(1 + cos(2at)), leading to L[cos(2at)] = s/(s² + (2a)²). The initial attempt mistakenly omitted the +2at term in the numerator, which is crucial for accurate transformation. The correct Laplace Transform is thus L[cos(2at)] = s/(s² + 4a²).

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Homework Statement


L[cos2at]

I know that L[cost] = s/(s2+bs)

I know that cos2at can also be written as 1/2(1+cos2at)

and so I then got the L[1/2]+1/2L[cos2at)]

Which gave me s/(s2+(2a)2)

However this is not correct, there was a + 2at term on the numerator as well.

Homework Equations





The Attempt at a Solution

 
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L[tn] = n!/sn+1

For L[1/2], n= 0 so you should get 1/2s as that transform.
 

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