Find the Laplace transform of \cos^2 t

Chesley

Chesley

Answered question

2021-09-04

Find the Laplace transform of cos2t

Answer & Explanation

unessodopunsep

unessodopunsep

Skilled2021-09-05Added 105 answers

Step 1
Solution
The laplace transform of
cos(at)ss2+a2 (1)
and for some constant k
kLaplaceks (2)
Step 2
Let f(t)=cos2(t) , Let say F(s) is laplace transform of f(t)
f(t)=cos2(t)
f(t)=12+cos(2t)2 (3)
[cos(2σ)=2cos2σ1]
Take Laplace trasform of f(t) as per equation (3)
From 1 and 2
F(s)=12s+12×ss2+22
F(s)=12s+s2(s2+4) (4)
Don Sumner

Don Sumner

Skilled2023-06-14Added 184 answers

Answer:
{cos2(t)}=12(1s+ss2+4)
Explanation:
{cos2(t)}={12(1+cos(2t))}
Now, let's find the Laplace transforms of each term separately.
Using the property {1}=1s, we have:
{1}=1s
Applying the cosine Laplace transform property {cos(at)}=ss2+a2, we have:
{cos(2t)}=ss2+22=ss2+4
Using the linearity property of Laplace transforms, we can combine the individual transforms:
{cos2(t)}=12({1}+{cos(2t)})=12(1s+ss2+4)
Therefore, the Laplace transform of cos2(t) is:
{cos2(t)}=12(1s+ss2+4)
Vasquez

Vasquez

Expert2023-06-14Added 669 answers

Step 1:
Given:
(cos2(t))=(12)+(12cos(2t))
Using the Laplace transform properties (1)=1s and (cos(at))=ss2+a2, we can simplify further:
(cos2(t))=12·1s+12·ss2+4
Step 2:
Combining the terms:
(cos2(t))=12s+s2(s2+4)
Therefore, the Laplace transform of cos2(t) is 12s+s2(s2+4).
nick1337

nick1337

Expert2023-06-14Added 777 answers

To find the Laplace transform of cos2(t), we can use the trigonometric identity cos2(t)=12(1+cos(2t)). Applying this identity, we have:
[cos2(t)]=[12(1+cos(2t))]
Now, we can use the linearity property of the Laplace transform to split the expression into two separate transforms:
[cos2(t)]=12[1]+12[cos(2t)]
The Laplace transform of a constant function 1 is given by:
[1]=1s where s is the complex frequency variable. Applying this result, we have:
[cos2(t)]=12·1s+12[cos(2t)]
Now, let's find the Laplace transform of cos(2t). The Laplace transform of cos(at) is given by:
[cos(at)]=ss2+a2
Using this result, we can calculate [cos(2t)]:
[cos(2t)]=ss2+22=ss2+4
Substituting this result back into our original equation, we have:
[cos2(t)]=12·1s+12·ss2+4
Combining the terms, we can simplify the expression further:
[cos2(t)]=12s+s2(s2+4)
Therefore, the Laplace transform of cos2(t) is given by 12s+s2(s2+4).

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