Final answer:
To sketch the functions C=f(x,t), we can choose specific values of x and t, plot C against t, and analyze the graphs to find maximum and minimum points.
Step-by-step explanation:
To sketch the functions, we can choose specific values of x and t to calculate C. Let's start with part (a), where we need to sketch f(2,t). Plugging in x=2, we have C=f(2,t)=2te^(-3t).
For part (b), we need to sketch f(x,1). Plugging in t=1, we have C=f(x,1)=xe^(-3).
In both cases, we should choose a range for t and plot C against t to obtain the graphs. For example, let's choose t values from 0 to 5 hours. We can use a computer program or calculator to plot these functions. Once the graphs are plotted, we can analyze them to find the maximum and minimum points.