The Student Room Group

Please check my C4 working

hello could u check my working for these 2 questions. i keep getting the 2nd one wrong but anyway:

1) integrate xe^(3x).dx

i got 1/3 e^(3x) (x - 1/3)

2) divide x^(4) + x^(3) - 5x^(2) - 9 by x^(2) + x - 6

did this by equating co-efficients (ax^2 + bx + c)

x^(4): 1 = a
x^(3): 1 = a + b
x^(2): -5 = -6a + b + c
x: 0 = -6b + c
no.s: -9 = -6c + r

a = 1
b = 0
c = 1
r = -3

so get (x^(2) + 1) (x^(2) + x - 6) - 3

this is so wrong and have done it 3 times! cant get the xs to cancel to get 0 x! help would be much appreciated. what am i doing wrong?
Reply 1
silly_billy
hello could u check my working for these 2 questions. i keep getting the 2nd one wrong but anyway:

1) integrate xe^(3x).dx

i got 1/3 e^(3x) (x - 1/3)


this is correct...
Reply 2
For (2) try using algebraic long division :smile: ...

Latest