Let A(c) denote the area of the region bounded from above by the line y = x

Question:

Let A(c) denote the area of the region bounded from above by the line y = x + 1, from the left by the y-axis, from below by the x-axis, and from the right by the line x = c. Such a function is called an accumulation Mutton. (See Figure 13.) Find
(a) A(1)
(b) A(2)
(c) A(0)
(d) A(c)
(e) Sketch the graph of A(c).
(f) What are the domain and range of A?