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#51 Re: Help Me ! » repeated linear factors, (i think) » 2013-11-20 01:31:25

hello bob

I HAVE TO use repeated linear factors, which is what I put in the first post.
I understand you saying use the easiest but repeated linear factors is what I have to use.
Thank you for your help. I have the answer, which I almost got in class. I ended it with negative 2.

its the method I don't understand.
That's what I have to show with the answer.

thanks for your help, all the best

simon

#52 Re: Help Me ! » repeated linear factors, (i think) » 2013-11-19 11:47:33

hello bob,

I have      14x-4x^2
              (1+x)(2-x)^2

I got A(2-x)^2 + B(2-x)(1+x) + C(1+x)

when I found A = -2, C = 4(I think, I cant remember)

the problem was B, I forgot to put that in.
I couldn't remember how to figure out the repeated linear factors bit.
so I replace each X with the opposite value and worked through the problem.
I cant remember how to do B

cheers.
simon

#53 Re: Help Me ! » repeated linear factors, (i think) » 2013-11-19 09:51:04

what I have to show is A+B or A-B, I thought it was A-B as I got a -B from the repeated factors bit.
should it be A-B?
so the answer is 2. but I cant get how im supposed to write the answer. that part I still don't understand. I get really confused when it comes to +/- signs and adding or subtracting them.

I have to write either A-B = -2 (-)2 meaning negative 2 take away positive 2. or A+B which is -2 + -2, which is negative 2 add negative 2.

I had to get the X^2 parts only to find this out.
I know the answers to A and C.
I didn't do the part for B.
I forgot to.
so I have to redo it.
im not sure if the A+B is specific to this sort of formula.

still confused!

thanks bob!!!

all the best simon

#54 Help Me ! » repeated linear factors, (i think) » 2013-11-19 08:20:58

ninjaman
Replies: 9

hello im having a problem with the last part of this assignment that I have.

I have this so far

14x -4x^2        A(2-X)^2 + B(1+X)(2-X) + C(1+X)
                       
                       A(4+4X+X^2) + B(2+1X-X^2) + C(1+X)

                       A4+4AX+AX^2 + B2+1BX-BX^2 +C(1+X)

I know that A is -2

so,            A-B = -4

somehow this is wrong, its most likely something that is staring me in the face but I cant think what it is

could it be that A+B, so it is the + that I left out. I thought that the -BX^2 meant -B so I put A-B

should it have been A+-B, which I think still gives the right answer?

my tutor explained it, but this part I didn't get and im struggling with the maths.

any help would really be appreciated!!!

thanks

all the best

simon:):):):):):)

#55 Help Me ! » geometric series » 2013-10-20 08:19:10

ninjaman
Replies: 1

hello

I have the first term of 30 and the last of 300, I have 7 speeds, 30 is first and 300 is last
I have to find the ratio, to find the middle speed.
im lost, should I be rearranging the formula?:)

#56 Re: Help Me ! » 2-x = x-2, is this correct? » 2013-10-20 04:56:20

im not sure how to write it, when x = 2-, is this correct

so would it be 2++1

so if I had (2-x)(1+x) and x = 2+ (instead of 2-)

it would be (2-+2) and (1++2)

is this correct, please could you point me in the right direction.

#57 Help Me ! » 2-x = x-2, is this correct? » 2013-10-20 04:19:50

ninjaman
Replies: 3

hello
I have to do another partial fraction but with (2-x)^2

im not sure if its

when x = 2-, or
when x = -2

it looks like (+2-x), it doesn't look like a minus. could it be that -x is treated as -1 so it becomes,

when x = +1 so it would be (2-+1) leaving just 1.

is this right im not sure.

I also have (1+x) and im not sure what to do with that either. can I just swap them like (x+1) that doesn't seem right though. after using 6 for x I get 7 either way. 1+6 or 6+1 but this doesn't work for the 2- as the answer would be the same just one would be minus the other positive. unless im completely confused on the matter......somethings cooking, smells like brain!!!

please help!!!

cheers
simon:)

#58 Help Me ! » partial fractions » 2013-10-19 08:08:55

ninjaman
Replies: 1

hello

I have 4x-15 / (x+3)(x+2)

I ended up with -27 for the first one which is A, though I think A is -A because the answer for that bracket is

when x=-3 (-3+2) = -1A, so, -27 = -A. do the minus's cancel leaving only 27? I always get confused with the minus's. is there somewhere with the rules for minus written down so I can memorise them?


and -23 for the second one which is B

any help would be greatly appreciated!!!

many thanks, hope your all well!!!

simon

and remember only two months left to Christmas!!!!

#59 Re: Help Me ! » arithmetic series » 2013-10-15 22:21:02

so expanding the brackets first

I haven't done a lot of math for a while and im getting thrown into the deep end, some of it is cooking my brain!!!
thank you for all your help

can you suggest a good site that shows how to rearrange formula and expand out the brackets. after putting the formula into the search engine, only advanced math sites come up.

all the best simon

#60 Help Me ! » arithmetic series » 2013-10-15 10:35:54

ninjaman
Replies: 5

hello
I have to answer a question using arithmetic series and im confused about the rearranging of forumlas. I haven't done a lot of this and would really appreciate the help!!!

the question is,
a body falling freely falls 5m in the first second of its motion, 15m in the second, and 25m during the third.

how long will it take to fall 3000m

I have the formula here, Sn = n/2 (2a+(n-1)d),

so with the values that I have, a being 5, d being 10 and Sn being 3000

I did this,  3000*2 = n(10+(n-1)10)

then         6000     = n(100+(n-1))
then                     100-1+n =99+n
so,            6000    = n 99+n
                           = n^2 +99-99
             6000-99 = n^2
             5901     = n^2
      (sqrt)5901   = (sqrt)n^2
       
to get,       n = 76.8179 seconds

again im not sure if this is correct so any help would be really appreciated!!!

thanks
all the best
simon:D

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