Heildi og flatarmál

c b a v 5 6 7 4 1 3 2 t 
#FIG 3.2
Landscape
Center
Metric
A4      
100.00
Single
-2
1200 2
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 630 2700 450 2700
2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 1 0 2
	0 0 1.00 120.00 120.00
	 45 2790 3915 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 450 2700 450 2745 450 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 630 2790 630 2610 810 2610
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 4
	 810 2790 810 2610 810 2430 990 2430
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 990 2790 990 2250 1170 2250
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 1170 2790 1170 2025 1350 2025
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 1350 2790 1350 1800 1530 1800
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 1530 1800 1530 1575 1710 1575
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 1710 2790 1710 1440 1890 1440
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 1890 2790 1890 1305 2070 1305
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 2070 2790 2070 1260 2250 1260
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 2250 2790 2250 1260 2430 1260
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 2790 2430 1260
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 2430 1305 2610 1305 2610 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 2610 1485 2790 1485 2790 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 1620 2970 1620
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2970 1620 2970 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 3330 2790 3330 1485 3510 1485
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3510 2790 3510 1485
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 3150 2790 3150 1440 3330 1440
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 3
	 2970 1620 2970 1530 3150 1530
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 1485 3330 1440
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 450 2790 540 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 720 2610 810 2700
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 630 2610 810 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 630 2700 720 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 900 2430 990 2520
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 810 2430 990 2610
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 810 2520 990 2700
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 810 2610 990 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 810 2700 900 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1170 2025 1350 2205
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1170 2115 1350 2295
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1170 2205 1350 2385
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1170 2295 1350 2475
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1170 2385 1350 2565
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1170 2475 1350 2655
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1170 2655 1305 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1170 2745 1215 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1260 2025 1350 2115
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1080 2250 1170 2340
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 990 2250 1170 2430
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 990 2340 1170 2520
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 990 2430 1170 2610
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 990 2520 1170 2700
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 990 2610 1170 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 990 2700 1080 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 1440 1890 1620
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 1530 1890 1710
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 1620 1890 1800
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 1710 1890 1890
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1800 1440 1890 1530
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 1800 1890 1980
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 1890 1890 2070
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 1980 1890 2160
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 2070 1890 2250
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 2160 1890 2340
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 2250 1890 2430
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 2340 1890 2520
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 2430 1890 2610
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 2520 1890 2700
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1710 2610 1890 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 1845 2070 2025
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 1935 2070 2115
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 2025 2070 2205
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 2115 2070 2295
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 2205 2070 2385
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 2295 2070 2475
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 2385 2070 2565
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 2475 2070 2655
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 2565 2070 2745
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 1755 2070 1935
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 1665 2070 1845
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 1575 2070 1755
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 1485 2070 1665
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 1395 2070 1575
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 1305 2070 1485
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1980 1305 2070 1395
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 2655 2025 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1890 2745 1935 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 1260 2430 1620
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 1350 2430 1710
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 1440 2430 1800
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 1530 2430 1890
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 1620 2430 1980
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 1710 2430 2070
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 1800 2430 2160
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 1890 2430 2250
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 1980 2430 2340
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 2070 2430 2430
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 2160 2430 2520
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 2250 2430 2610
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 2340 2430 2700
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 2430 2430 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 2520 2250 2700
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 2610 2250 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2250 1350 2430 1530
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2250 1260 2430 1440
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2340 1260 2430 1350
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2160 1260 2250 1350
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2250 2700 2340 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2070 2700 2160 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2520 1305 2610 1395
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 1305 2790 1665
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2700 1485 2790 1575
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 1395 2790 1755
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 1485 2790 1845
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 1575 2790 1935
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 1665 2790 2025
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 1755 2790 2115
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 1845 2790 2205
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 1935 2790 2295
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 2025 2790 2385
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 2115 2790 2475
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 2205 2790 2565
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 2295 2790 2655
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 2385 2790 2745
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 2475 2745 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 2565 2655 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 2655 2565 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2430 2745 2475 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3150 1440 3330 1620
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3240 1440 3330 1530
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3150 1530 3330 1710
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3060 1530 3330 1800
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2970 1530 3330 1890
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2970 1620 3330 1980
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2880 1620 3330 2070
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 1620 3330 2160
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 1710 3330 2250
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 1800 3330 2340
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 1890 3330 2430
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 1980 3330 2520
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 2070 3330 2610
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 2160 3330 2700
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 2250 3330 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 2340 3240 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 2430 3150 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 2520 3060 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 2610 2970 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 2790 2700 2880 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3420 1485 3510 1575
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 1485 3510 1665
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 1575 3510 1755
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 1665 3510 1845
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 1755 3510 1935
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 1845 3510 2025
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 1935 3510 2115
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 2025 3510 2205
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 2115 3510 2295
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 2205 3510 2385
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 2385 3510 2565
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 2475 3510 2655
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 2565 3510 2745
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 2655 3465 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 2745 3375 2790
2 1 0 1 8 7 50 0 -1 4.000 0 0 -1 0 0 2
	 450 2700 540 2790
2 1 0 1 8 7 50 0 -1 4.000 0 0 -1 0 0 2
	 540 2700 630 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 3330 2295 3510 2475
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1665 2700 1755 2790
2 1 1 1 1 7 50 0 -1 4.000 0 0 -1 0 0 2
	 1530 1800 1530 2790
2 1 0 1 8 7 50 0 -1 0.000 0 0 -1 0 0 2
	 1170 2565 1350 2745
2 1 0 1 10 7 50 0 -1 0.000 0 0 -1 0 0 2
	 630 2835 630 2790
2 1 1 1 10 7 50 0 -1 4.000 0 0 -1 0 0 2
	 810 3060 810 2790
2 1 0 1 10 7 50 0 -1 0.000 0 0 -1 0 0 2
	 990 2835 990 2790
2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 1 0 2
	0 0 1.00 120.00 120.00
	 450 3060 450 720
2 1 1 1 10 7 50 0 -1 4.000 0 0 -1 0 0 2
	 450 2250 990 2250
2 1 1 1 10 7 50 0 -1 4.000 0 0 -1 0 0 2
	 450 2430 810 2430
2 1 1 1 10 7 50 0 -1 4.000 0 0 -1 0 0 2
	 450 2610 630 2610
3 0 0 1 23 7 50 0 -1 4.000 0 1 0 4
	0 0 1.00 120.00 120.00
	 3015 1170 3015 1305 2925 1485 2520 1890
	 0.000 1.000 1.000 0.000
3 0 0 1 23 7 50 0 -1 0.000 0 1 0 4
	0 0 1.00 120.00 120.00
	 1080 1350 990 1620 990 1890 1080 2475
	 0.000 1.000 1.000 0.000
3 0 0 1 20 7 50 0 -1 0.000 0 0 0 12
	 450 2790 720 2700 1080 2385 1575 1755 1890 1395 2430 1170
	 2790 1440 2970 1710 3240 1440 3330 1440 3555 1485 3645 1530
	 0.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000
	 1.000 1.000 1.000 0.000
4 0 0 50 0 0 12 0.0000 4 90 90 225 2475 c\001
4 0 0 50 0 0 12 0.0000 4 135 90 225 2655 b\001
4 0 0 50 0 0 12 0.0000 4 90 90 225 2745 a\001
4 0 0 50 0 0 12 0.0000 4 90 90 225 855 v\001
4 0 0 50 0 0 12 0.0000 4 135 90 810 1260 5\001
4 0 0 50 0 0 12 0.0000 4 135 90 2700 1080 6\001
4 0 0 50 0 0 12 0.0000 4 135 90 3195 3015 7\001
4 0 0 50 0 0 12 0.0000 4 135 90 225 2295 4\001
4 0 0 50 0 0 12 0.0000 4 135 90 495 3015 1\001
4 0 0 50 0 0 12 0.0000 4 135 90 855 3015 3\001
4 0 0 50 0 0 12 0.0000 4 135 90 720 3240 2\001
4 0 0 50 0 0 12 0.0000 4 105 60 3915 3015 t\001
Gerum nú ráð fyrir að við þekkjum hraðann og viljum komast að því hversu langt faratæki hefur farið á $T$ mín.
Details
Gerum nú ráð fyrir að við þekkjum hraðann og viljum komast að því hversu langt faratæki hefur farið á $T$ mín.\\

Hraðinn þegar $t=0$ er $0$. Mælum hraðann með jöfnu millibili $\Delta t$ (þar sem gert er ráð fyrir að $\Delta t$ sé lítið þ.a. hraðinn breytist ,,lítið`` innan hvers bils).\\\\
G.r.f. að hraðinn þegar $t = i\cdot \Delta t$ sé $v_i$. Vegalengdin sem farartækið fer 1. tímabilið er $\approx v_1\cdot\Delta t$, 2. tímabilið $\approx v_2\cdot \Delta t$ o.s.frv. (Ath! þetta er ekki nákvæmt!).\\\\
Við getum því nálgað heildarvegalengdina sem farin er á tímanum $T$ ($=n\cdot \Delta T$) með
\begin{eqnarray*}
&v_1\Delta t + v_2\Delta t + \cdots + v_{n-1}\Delta t + v_n \Delta t\\
&= (v_1 + v_2 + \cdots + v_n)\Delta t
\end{eqnarray*}
Ath:
$v_i$ er hæð grafsins í $t_i = i\cdot \Delta t$. Því er $v_i \Delta t$ flatarmálrétthyrnings með grunnlínu $\Delta t$ og hæð $v_i$.\\\\
Heildarvegalengdina sem er farin má því \textbf{nálga} með flatarmáli allra rétthyrninganna (summu flatarmálanna). En við sjáum líka að summa flatarmála rétthyrninganna er nálgun á flatarmálinu undir grafinu $v = v(t)$. Við gætum e.t.v. fengið betri nálgun á heildarvegalengdinni með því að mæla hraðann í miðpunkti hvers bils (meðalhraði í bilinu $[(i - 1)\Delta t, i\Delta t]$ ), en hugmyndin er sú sama.\\
Ath:
Ef $v(t)$ er þekkt fall af $t$, þá er vegalengdin $s(t)$ stofnfall $v(t)$.\\
Spurning:
Er samband á milli stofnfalls $f(t)$ og flatarmáls undir grafinu $f = f(t)$?
\begin{itemize}
\item $s(t) = \int v(t) \, dt$ \qquad (g.r.f. $v(0) = 0$). Heildarvegalengd er $s(T)$.
\item $s(T)$, heildarvegalengd, er flatarmálið undir $v = v(t)$, $0\leq t\leq T$.
\end{itemize}