For each of the following functions and intervals: Compute [math]\int_a^b f(x) \; dx[/math]; draw the graph of [math]f[/math]; label the region [math]P^-[/math] on or below the [math]x[/math]-axis which is bounded by the curve [math]y = f(x)[/math], the [math]x[/math]-axis, and the lines [math]x = a[/math] and [math]x = b[/math]; label the analogous region [math]P^-[/math] on or below the [math]x[/math]-axis; evaluate [math]\mbox{''area''}(P^+)[/math] and [math]\mbox{''area''}(P^-)[/math]; and check formula.
- [math]f(x) = x - 1[/math], [math]a = 0[/math], and [math]b = 4[/math].
- [math]f(x) = -x^2 + x + 2[/math], [math]a = 0[/math], and [math]b = 3[/math].
- [math]f(x) = -x^2 + x + 2[/math], [math]a = -2[/math], and [math]b = 3[/math].
- [math]f(x) = (x - 1)^3[/math], [math]a = 0[/math], and [math]b = 2[/math].
In each of the following find the area of the subset [math]P^+ \cup P^-[/math] of the [math]xy[/math]-plane bounded by the curve [math]y = f(x)[/math], the [math]x[/math]-axis, and the lines [math]x = a[/math] and [math]x = b[/math].
- [math]f(x) = x^5[/math], [math]a = -1[/math], and [math]b = 1[/math].
- [math]f(x) = x^2 - 3x + 2[/math], [math]a = 0[/math], and [math]b = 2[/math].
- [math]f(x) = (x + 1)(x - 1)(x - 3)[/math], [math]a = 0[/math], and [math]b = 2[/math].
- [math]f(x) = |x^2 - 1|[/math], [math]a = -2[/math], and [math]b = 2[/math].
Let [math]f[/math] be a continuous function. Using areas, show that
- lab{4.7.3a} If [math]f[/math] is an odd function, then [math]\int_{-a}^a f(x) \; dx = 0[/math].
- lab{4.7.3b} If [math]f[/math] is an even function, then [math]\int_{-a}^a f(x) \; dx = 2 \int_0^a f(x) \; dx[/math].
Prove \ref{ex4.7.3a} and \ref{ex4.7.3b} analytically using the Fundamental Theorem of Calculus. [More specifically, use Theorems and.]
Draw the region [math]R[/math] bounded by the lines [math]x = 0[/math] and [math]x = 2[/math] and lying between the graphs of the functions [math]f(x) = x + 2[/math] and [math]g(x) = (x - 1)^2[/math]. Find the area of [math]R[/math].
Draw the region [math]Q[/math] lying to the right of the [math]y[/math]-axis and bounded by the curves [math]x = 0[/math], [math]3y - x + 3 = 0[/math], and [math]3y + 3x^2 - 8x = 3[/math]. Compute [math]\mbox{''area''}(Q)[/math].
Find the area of the subset [math]R[/math] of the [math]xy[/math]-plane lying between the lines [math]x = \frac12[/math] and [math]x = 2[/math], and between the graphs of the functions [math]f(x) = \frac1{x^2}[/math] and [math]g(x) = x^2[/math]. Draw the relevant lines and curves and indicate the region [math]R[/math].
Find the area of the region bounded by the two parabolas [math]y = -x^2 + x + 2[/math] and [math]y = x^2 - 2x[/math].
Draw the graphs of the equations [math]y = x^2[/math] and [math]y = 4[/math], and label the region [math]R[/math] bounded by them.
- lab{4.7.9a} Express the area of [math]R[/math] as an integral with respect to [math]x[/math] using \ref{thm 4.7.1}. Evaluate the integral.
- Similarly, express the area of [math]R[/math] as an integral with respect to [math]y[/math] using the counterpart of \ref{thm 4.7.1} for functions of [math]y[/math]. Evaluate the integral and check the answer to \ref{ex4.7.9a}.
- If [math]f(y) = -y^2 + y + 2[/math], sketch the region bounded by the curve [math]x = f(y)[/math], the [math]y[/math]-axis, and the lines [math]y = 0[/math] and [math]y = 1[/math]. Find its area.
- Find the area bounded by the curve [math]x = -y^2 + y + 2[/math] and the [math]y[/math]-axis.
- The equation [math]x + y^2 = 4[/math] can be solved for [math]x[/math] as a function of [math]y[/math], or for [math]y[/math] as plus or minus a function of [math]x[/math]. Sketch the region in the first quadrant bounded by the curve [math]x + y^2 = 4[/math], and find its area first by integrating a function of [math]y[/math] and then by integrating a function of [math]x[/math].