15.1	b) integral ln x dx from 1 to e
	c) integral sqrt(1-x^2)/x^2 dx x from 1/2 to 1
	d) integral x^3*cos(x/2) dx from 0 to pi
	
15.2	a) integral (8x^2015+sin x) dx x from -1 to 1
	c) integral (5x/(4+x^2)^2) dx x from -1 to 1
	d) integral ((x^2+1)/(x^2-4)) dx x from 0 to 1
	e) integral sin(x/2)/cos^2(x/2) dx x from 0 to pi/2
	f) integral 1/(e^x-e^(-x)) dx where x from ln 2 to ln 3
	g) integral (x+4)sqrt(x^2+8x+7) dx where x from -1 to 0
	h) integral x*sin x*cos x dx where x from -pi to pi
	i) integral e^(-x)*cos (2x) dx x from 0 to pi
	j) integral sqrt(cos  x - cos^3 x) dx from -pi/2 to pi/3
	k) integral (x+3)/(x^2+4) dx from 0 to 2

15.6	plot x^2+9y^2=9
	integral sqrt((9-x^2)/9) dx from -3 to 3
	
15.11	a) integral cos^2 x dx
	b) cos^3 x / 3 - cos^5 x / 5 + integral sin^3x*cos^2 x dx
	c) integral sin^4x dx
	f) integral sin(2x)/cos^3 x dx
	g) integral sin^2x*cos^2x dx

16.1	b) 	plot x,3-x
		integral 3-2x dx from 0 to 1.5
	c) 	plot[{x^2/2+2,4},{x,0,2}]
		integral 4-(x^2/2+2) dx from 0 to 2
	f) 	plot[{x^2,x^3},{x,0,1}]
		integral x^2-x^3 dx from 0 to 1
	g) 	plot[{3/x^2,0},{x,2,3}]
		integral 3/x^2 dx from 2 to 3
	h) 	plot[{sqrt(x-1),3-x,0},{x,1,3}]
		integral sqrt(x-1) dx from 1 to 2 + integral 3-x dx from 2 to 3
	i) 	plot[{x^5/2,0},{x,-1,2},{y,-1,16}]
		-integral x^5/2 dx from -1 to 0 + integral x^5/2 dx from 0 to 2
	j) 	plot[{x^2,-(-x)^(1/3),x^(1/3)},{x,-2,2}]
		integral x^2-x^{1/3} dx from -2 to 0 + integral x^{1/3}-x^2 dx from 0 to 1+integral x^2-x^{1/3} dx from 1 to 2
	k) 	plot[{sqrt(x^4(1-x^3)),-sqrt(x^4(1-x^3))},{x,-1,2}]
		2*integral x^2*sqrt(1-x^3) dx from 0 to 1

16.2	polar plot r=2sin theta where theta from pi/4 to pi/2
	1/2*integral 4sin^2x dx from pi/4 to pi/2

16.5	PolarPlot[{r=2sin (3*theta),r=2|sin (3*theta)|},{theta,0,pi}]
	1/2*integral 4sin^2(3x) dx from 0 to pi	

16.6	PolarPlot[{r=1+cos theta,r=cos theta},{theta,0,2pi}]
	PolarPlot[{r=1+cos theta,r=cos theta},{theta,0,pi}]
	1/2*(integral (1+cos x)^2 dx from 0 to 2pi) - 1/2*(integral cos^2 x dx from 0 to pi)