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Consider a two-sector model

Yt = Ct + It
Ct = 0.7Yt-1 + 400
It = 0.1Yt-1 + 200.
Find an expression for Yt when Y0 = 3000. Is the system stable?

1 Answer

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Final answer:

To find an expression for Yt, substitute the expressions for Ct and It into the equation for Yt. Calculate Y1, Y2, and so on using the equation Yt = 0.8Yt-1 + 600. The system is stable as it converges to a steady-state value.

Step-by-step explanation:

The two-sector model is represented by the equations:

Yt = Ct + It

Ct = 0.7Yt-1 + 400

It = 0.1Yt-1 + 200

To find an expression for Yt, we can substitute the expressions for Ct and It into the equation for Yt:

Yt = 0.7Yt-1 + 400 + 0.1Yt-1 + 200

Simplifying the equation, we get:

Yt = 0.8Yt-1 + 600

Given that Y0 = 3000, we can calculate Y1, Y2, and so on using the equation:

Yt = 0.8Yt-1 + 600

Therefore, Y1 = 0.8 * 3000 + 600 = 3000 + 600 = 3600

Similarly, Y2 = 0.8 * 3600 + 600 = 2880 + 600 = 4200

Y3 = 0.8 * 4200 + 600 = 3360 + 600 = 4800

...

The system is stable because it converges to a steady-state value, which is 6000 in this case.

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