f.5 definite integration

2010-11-20 6:38 am
Find the total area of the shaded region(ans: 67/8)
http://i729.photobucket.com/albums/ww291/kaka1307/0070.jpg
thanks a lot!
更新1:

pls show clear steps~

回答 (2)

2010-11-20 6:51 am
1 The intersection points are (1,0) and (7/2,-5/4)

For the first region, the area is
∫ (x^2-5x+4)-(-x^2+4x-3) dx [x from 0 to 1]
=∫ (2x^2-9x+7) dx
=(2/3)x^3-(9/2)x^2+7x | [0,1]
=19/6

the area of the second shaded region is
∫ (-x^2+4x-3)-(x^2-5x+4) dx [x from 1 to 7/2]
=∫ (-2x^2+9x-7) dx
=(-2/3)x^3+(9/2)x^2-7x | [1,7/2]
=(49/24)-(-19/6)
=125/24

The total area is
19/6+125/24
=67/8


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