Post Last Edit by lavender_aqua at 22-3-2012 00:12
2. (1)
x^2(x^2-4) + x + 1 = x^2 + x+1
x^2-4 (x-2)(x+2)
using partial fraction:
x+1 = A + B (2)
(x-2)(x+2) (x-2) (x+2)
x+1=A(x+2) + B(x-2)
when x=-2
-1=-4B
B = 1/4
when x=2
3=4A
A=3/4
substitute back in (2)
x+1 = 3 + 1
(x-2)(x+2) 4(x-2) 4(x+2)
integration of (1)= x^3 + 3 ln (x-2) + ln (x+2) + C
3 4 4
* nak juga jwb walaupun dah lambat... |