1.
Let f(x)={x2+4:x<042x:x0f(x) = \begin{cases} x^2 + 4 & : x < 0 \\ 4 - 2x & : x \geq 0 \end{cases}, then the area bounded by y=f(x)y = f(x) and the xx-axis from x=1x = -1 to x=3x = 3 is equal to