We assume you want to find the inverse transform of s/(s^2 +3s -4). This can be written in partial fraction form as
(4/5)/(s+4) + (1/5)/(s-1)
which can be found in a table of transforms to be the transform of
(4/5)e^(-4t) + (1/5)e^t
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There are a number of ways to determine the partial fractions. They all start with factoring the denominator.
s^2 +3x -4 = (s+4)(s-1)
After that, you can postulate the final form and determine the values of the coefficients that make it so. For example:
A/(s+4) + B/(s-1) = ((A+B)s + (4B-A))/(s^2 +3x -4)
This gives rise to two equations:
(A+B) = 1
(4B-A) = 0
4b²+20b+25=0
Divide everything by 4
b²+5b+ 6.25=0
use the quadratic formula
x= (-b+ or - √b²-4ac) /2a
x= (-5 + or - √5²-4*1*6.25) /2(1)
x= -5/2 so
in this case, b= -5/2
Answer:
Step-by-step explanation:
51 / 13 = 3.9231 = 3
51 - (13 x 3) = 12
simplify to 1 hour which will be 6 minutes in 1 hour
in 3 hours it will be 18 minutes
