10 SCREEN 12
20 WINDOW (-1, 6)-(17, -20)
25 DEFDBL A-Z
30 FOR x = 0 TO 3 STEP .005
40 y = (9 * x) ^ (1 / 2)
50 a = -1 * ((9 * x) ^ (1 / 2))
60 PSET (x, y)
70 PSET (x, a)
80 NEXT x
90 LINE (-1, 0)-(5, 0)
100 LINE (0, 5)-(0, -5)
110 LINE (3, 5.1962)-(3, -5.1962)
115 LOCATE 1, 20
120 PRINT "Disk Formula for Volume of a Solid of Revolution"
122 LOCATE 5, 10
123 PRINT "y^2=9x"
124 LOCATE 7, 18
125 PRINT "x=3"
130 LOCATE 15, 1
140 PRINT "The Disk Formula for volume V of a solid of revolution about the x axis is"
150 PRINT "   "; CHR$(244); "b             "; CHR$(244); "b"
160 PRINT "V="; CHR$(227); CHR$(245); "a (f(x))^2dx="; CHR$(227); CHR$(245); "a y^2dx"
170 PRINT "Example: Volume for y^2=9x revolved about the x axis to x=3"
180 PRINT "   "; CHR$(244); "3        "; CHR$(244); "3               "; CHR$(179); "3"
185 b = 40.5 * 3.141592653589793#
190 PRINT "V="; CHR$(227); CHR$(245); "0 y^2dx="; CHR$(227); CHR$(245); "0 9xdx="; CHR$(227); "(4.5x^2)"; CHR$(179); "0 ="; CHR$(227); "(40.5-0)= "; b
200 SYSTEM