Solve L(sin4t) ?

1 Answer
Apr 12, 2018

Guessing this is a Laplace transform request

Explanation:

#mathbb L {cos omega t color(red)(-) i sin omega t } = mathbb L {e^(-i omega t) } #

#= int_0^(oo) e^(-(i omega +s)t) \ dt #

# = - (1)/(i omega + s) [ e^(-(i omega +s)t)]_0^(oo)#

# = (1)/(i omega + s) = (s - i omega)/(s^2 + omega ^2)#

#implies mathbb L {cos omega t } = \mathcal (Re) (mathbb L {cos omega t color(red)(-) i sin omega t } )= (s )/(s^2 + omega ^2)#

AND

#implies mathbb L {sin omega t } = -\mathcal (Im) (mathbb L {cos omega t color(red)(-) i sin omega t } )= (omega )/(s^2 + omega ^2)#

Repeat for: #omega = 4#