M Mr Chi New Member Joined Nov 15, 2005 Messages 28 Gender Male HSC 2006 Nov 26, 2005 #1 ( 4x^3+3x^2+5/x^2 dx ) I cant get these sought of ones can someone please help?
insert-username Wandering the Lacuna Joined Jun 6, 2005 Messages 1,226 Location NSW Gender Male HSC 2006 Nov 26, 2005 #2 You need to write out the individual parts of the fraction, cancel common factors, and then write in terms of negative indices if necessary: ( ) (4x3 + 3x2 + 5)/x2 dx = ( ) (4x3)/x2 + (3x2)/x2 + 5/x2 dx = ( )(4x + 3 + 5x-2) dx = 2x2 + 3x - 5x-1 I_F Last edited: Nov 26, 2005
You need to write out the individual parts of the fraction, cancel common factors, and then write in terms of negative indices if necessary: ( ) (4x3 + 3x2 + 5)/x2 dx = ( ) (4x3)/x2 + (3x2)/x2 + 5/x2 dx = ( )(4x + 3 + 5x-2) dx = 2x2 + 3x - 5x-1 I_F
P pLuvia Guest Nov 26, 2005 #3 ∫ [4x3+3x2+5/x2] dx Is this what you mean? If so ∫ [4x3+3x2+5/x2] dx = x4+x3-5/x + C If it's ∫ [4x3+3x2+5]/[x2] dx = ∫ [4x3/x2+3x2/x2+5/x2] dx = ∫ [4x + 3 + 5x-2]dx = 2x2 + 3x - 5x-1 +C = 2x2 + 3x - 5/x +C P.S insert-username you forgot to add C the constant
∫ [4x3+3x2+5/x2] dx Is this what you mean? If so ∫ [4x3+3x2+5/x2] dx = x4+x3-5/x + C If it's ∫ [4x3+3x2+5]/[x2] dx = ∫ [4x3/x2+3x2/x2+5/x2] dx = ∫ [4x + 3 + 5x-2]dx = 2x2 + 3x - 5x-1 +C = 2x2 + 3x - 5/x +C P.S insert-username you forgot to add C the constant
insert-username Wandering the Lacuna Joined Jun 6, 2005 Messages 1,226 Location NSW Gender Male HSC 2006 Nov 27, 2005 #4 Damn. Damn Damn Damn Damn Damn. I always forget the bloody constant! I_F
R Riviet . Joined Oct 11, 2005 Messages 5,593 Gender Undisclosed HSC N/A Nov 27, 2005 #5 Don't forget again.
insert-username Wandering the Lacuna Joined Jun 6, 2005 Messages 1,226 Location NSW Gender Male HSC 2006 Nov 27, 2005 #6 I was doing some integration today, and I kept leaving it out! So friggin' annoying! Automatic one mark off! I_F
I was doing some integration today, and I kept leaving it out! So friggin' annoying! Automatic one mark off! I_F
P pLuvia Guest Nov 28, 2005 #7 lol, just keep practicing , just make a note before you do those questions in a test usually works if you remember to write it down
lol, just keep practicing , just make a note before you do those questions in a test usually works if you remember to write it down