題組內容

3. Consider a closed economy described by the Solow growth framework in continuous time. Output is produced using a Cobb-Douglas technology: $$Y = K^{\alpha} N^{1-\alpha}, \quad 0 < \alpha < 1$$ where Y represents total output, K denotes the capital stock, and $N$ is the labor force (number of workers). The parameter $\alpha$ measures capital's share in output. The population grows at a constant rate $n > 0$, i.e., $\dot{N}/N = n$. Capital accumulates according to: $$\dot{K} = I - \delta K$$ where I is total investment and $\delta \in (0,1)$ is the constant rate of capital depreciation. National saving is defined as a constant fraction of output: $$S = sY$$ where $s \in (0,1)$ is the savings rate. We assume the goods market clears such that S = I. Please answer the following questions:

(b) Determine the long-run growth rates of output per worker \( y \) and total output \( Y \). Based on your results, explain why the Solow model is classified as an exogenous growth model. (10%)