Tutor.com Functions Session

Mar. 19, 2012

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Session Transcript - Math - Calculus, 3/12/2012 11:13AM - Tutor.comSession Date: 3/12/2012 11:13AM
Length: 22.6 minute(s)
Subject: Math - Calculus


System Message
[00:00:00] *** Please note: All sessions are recorded for quality control. ***

Joshua (Customer)
[00:00:00] I am supposed to be finding a fifth degree polynomial with 5i, 1-3i, and -1 as zeros. I know that -5i and 1+3i are the other two zeros because of the conjugate pairs theorem however when it comes to simplifying I keep getting the wrong answers. I am using MyMathLab and this is the new problem it has generated for me. Will you help walk me through it so I can see what I am doing wrong?

Aaron L (Tutor)
[00:00:14] hello

Joshua (Customer)
[00:00:18] Hi!

Aaron L (Tutor)
[00:00:18] how are you doing today

Joshua (Customer)
[00:00:25] Good, thanks, how are you?

Aaron L (Tutor)
[00:00:28] I am good
[00:00:40] welcome to tutor.com
[00:00:46] lets get started
[00:01:03] ok....
[00:01:14] so we are looking for a 5th degree polynomial
[00:01:26] and it looks like you have the 5 roots
[00:01:28] correct?

Joshua (Customer)
[00:01:31] Yes

Aaron L (Tutor)
[00:02:52] so then these would be the factors
[00:02:55] do you agree?

Joshua (Customer)
[00:02:59] Yes

Aaron L (Tutor)
[00:03:11] so now.....
[00:03:18] we have to do a lot of distributing

Joshua (Customer)
[00:03:27] Since it is multiplication, it doesnt matter where we start? Or does it?

Aaron L (Tutor)
[00:03:34] it doesnt
[00:03:36] however
[00:03:54] it will be easier if we multiply our pairs first

Joshua (Customer)
[00:04:17] Oh, I forgot to add that for the polynomial f(0) should equal 750

Aaron L (Tutor)
[00:04:37] I dont see that part in the problem?

Joshua (Customer)
[00:04:45] No I forgot to add that....sorry

Aaron L (Tutor)
[00:05:23] so do you know what is wrong then with this problem/
[00:05:30] are you able to solve it now?

Joshua (Customer)
[00:05:55] I dont know. I always get this far, then I end up with an answer that meets the conditions but is wrong...

Aaron L (Tutor)
[00:06:15] we letws foil this trinomial
[00:08:07] do you agree with this method in foiling the last part

Joshua (Customer)
[00:08:10] Should that be 9i^2?

Aaron L (Tutor)
[00:08:18] yes...thank you
[00:09:11] so this is what it breaks down into...agreed?

Joshua (Customer)
[00:09:15] Yes

Aaron L (Tutor)
[00:09:36] correct
[00:09:40] and in order it would be
[00:10:29] so now we have to multiply this 4 term by 3 term

Brian M (Tutor)
[00:14:47] Hello,

Joshua (Customer)
[00:14:52] Hi!

Brian M (Tutor)
[00:15:01] Let me just take a look at what you have already done

Joshua (Customer)
[00:15:14] I am just trying to make sure I did this correctly...I am entering it in MyMathLab to check...

Brian M (Tutor)
[00:15:27] Okay then I will wait for you

Joshua (Customer)
[00:16:09] Well it said its not right... ...Im not sure what I did wrong though...

Brian M (Tutor)
[00:16:22] Alright I am looking it over now. Give me just a sec

Joshua (Customer)
[00:16:27] Sure

Brian M (Tutor)
[00:17:09] Well it is correct it is not right. Let me find the error. Just a min
[00:17:24] The program is correct I mean.

Joshua (Customer)
[00:17:53] Wow....that would be 75
[00:17:57] Oops

Brian M (Tutor)
[00:18:23] Well that is closer but still not quite right
[00:18:35] Let me find exactly where the mistake it and we will fix it up'
[00:20:05] Ahhh found it

Joshua (Customer)
[00:20:06] Ok I found the problem. I missed the negative sign I wrote in for 50 x squared.

Brian M (Tutor)
[00:20:15] right you are !

Joshua (Customer)
[00:20:16] MathLab says its right too so yay!!

Brian M (Tutor)
[00:20:22] Great job finding it!

Joshua (Customer)
[00:20:26] Thanks!

Brian M (Tutor)
[00:20:39] No problem. Any questions about anything?

Joshua (Customer)
[00:20:44] Yes actually

Brian M (Tutor)
[00:20:50] Alrighty shoot!

Joshua (Customer)
[00:21:05] If I am writing out factors of a polynomial, does it matter what order they are in?

Brian M (Tutor)
[00:21:23] Nope

Joshua (Customer)
[00:21:33] I have gotten problems wrong for writing(x-(3-5i)) before (x- (3+5i))

Brian M (Tutor)
[00:21:36] Since multiplcation is commutative, it doesn't matter

Joshua (Customer)
[00:21:48] Thats what I thought...

Brian M (Tutor)
[00:22:16] well your teacher may say that he or she wants it a certain way so they can read it easier, or the program just may be too dumb to figure it out, but technically both are correct

Joshua (Customer)
[00:22:35] Haha maybe so....

Brian M (Tutor)
[00:22:36] That would be like saying ab is correct but ba is wrong

Joshua (Customer)
[00:22:44] Ok Im good to go now! thanks again!

Brian M (Tutor)
[00:23:05] No problem! You did a really good job! Havea great day!

Joshua (Customer)
[00:23:12] Thanks!! You too!!