Solve yn yn1 003yn1 007 y0 y0Solutiongiven yn yn1 003y
Solve y_n - y_n-1 = 0.03y_n-1 - 0.07, y(0) = y_0
Solution
given yn - y(n-1) = 0.03y(n-1) -0.07 ------>equation1
now plug n=n-1 in the above equation
we get y(n-1) -y(n-2) =0.03(n-2) -0.07 ----->equation2
now subtract equation2 from equation 1
y(n-1) -y(n-2) -0.03(n-2) +0.07 - -[ yn - y(n-1) - 0.03y(n-1) +0.07 ]=0
y(n-1) -1.03y(n-2) +0.07 -yn +1.03y(n-1) -0.07 =0
2.03y(n-1) -1.03y(n-2) -yn=0
now let us say yn = x^n
2.03 x^n-1 -1.03 x^n-2 -x^n =0
x^n [ 2.03/x -1.03/x^2 -1]=0
[2.03x -1.03 -x^2]=0
x^2 -2.03x +1.03=0
x^2 -1x -1.03x+1.03=0
x(x-1) -1.03(x-1)=0
(x-1)(x-1.03)=0
x= 1 or x=1.03
then yn = A(1)^n +B(1.03)^n
we have to find out A,B value from y(0) value
plug n=0
y0 = A+B
y1 = 1.03y0 -0.07
plug n=1
1.03y0 -0.07 = A+1.03B
solve and get A and B value in terms of y0
