Tutor.com Exponential and Logarithmic Functions Session

Apr. 9, 2012

Session Transcript - Math - Algebra II, 3/28/2012 10:56PM - Tutor.comSession Date: 3/28/2012 10:56PM
Length: 31.2 minute(s)
Subject: Math - Algebra II

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

Guest (Customer)
[00:00:00] help to solve a radical problem

Richard H (Tutor)
[00:00:06] Hello, and welcome to Tutor.com

Guest (Customer)
[00:00:06] hello

Richard H (Tutor)
[00:00:15] Hi! Radical problem, no problem!

Guest (Customer)
[00:00:47] lol i did it i just want to know if how i did it was right
[00:00:54] ill wirte it down

Richard H (Tutor)
[00:00:59] Sure thing
[00:05:14] Hmm, I see what you did there, but remember that the 15.7 is being multiplied by the root

Guest (Customer)
[00:05:52] oh ok

Richard H (Tutor)
[00:06:32] Also, to be sure, I see that you used pi = 3.14 there. Though technically correct, depending on the situation, its possible that it may be better to leave it as pi for now.

Guest (Customer)
[00:07:16] ok

Richard H (Tutor)
[00:07:40] The reason: it's easier to work with and simplify other terms if there's no decimals involved. We can always apply it at the end if necessary. In most cases, leaving it as pi all the way is fine

Guest (Customer)
[00:08:25] so will i divide?
[00:08:29] the 5

Richard H (Tutor)
[00:08:54] Yeah, we may as well divide by 5pi though, since we want to isolate the term that includes the variable

Guest (Customer)
[00:10:54] ok so like this?

Richard H (Tutor)
[00:10:59] Yeah

Guest (Customer)
[00:11:08] ok

Richard H (Tutor)
[00:11:27] Now what can we do from here?

Guest (Customer)
[00:12:12] does the 5^2 inside the radical turns into 25 ?

Richard H (Tutor)
[00:12:18] Yeah

Guest (Customer)
[00:12:22] cool

Richard H (Tutor)
[00:14:11] Ah, I see what you did there, but I'm afraid we can't do that. We can take out something from the root only if it is a factor of everything inside the root

Guest (Customer)
[00:14:34] alright
[00:15:11] so do i um...
[00:15:33] square both sides?

Richard H (Tutor)
[00:16:09] Yeah, that works fine! Don't forget that the pi is being multiplied by the root though. That means we'll have to move it to the left at some point anyways. It can be done before or after squaring, its fine either way!

Guest (Customer)
[00:16:47] ok cool

Richard H (Tutor)
[00:16:50]
[00:17:03] Pick a path and go for it!

Guest (Customer)
[00:17:33] think i should divide the pi first?

Richard H (Tutor)
[00:18:03] I would do that myself, habit of doing all isolating before taking square roots or exponents.

Guest (Customer)
[00:18:18] aright
[00:19:47] looks good?

Richard H (Tutor)
[00:19:52] Yeah!

Guest (Customer)
[00:19:58] alright!!!
[00:21:08] good
[00:22:40] do i square again?

Richard H (Tutor)
[00:23:00] If you mean to take the square root, then yes!

Guest (Customer)
[00:23:14] alright!

Richard H (Tutor)
[00:23:51] Take the square root, don't square it. To cancel an exponent of 2 (a squared term), we take the square root

Guest (Customer)
[00:24:45] ok confused

Richard H (Tutor)
[00:25:11] Remember, to square something is to raise it to the 2nd power. To take the square root is this:
[00:25:53] Just like you raised it to the 2nd power to cancel the square root a few steps before, we can take the square root to cancel a 2nd power.

Guest (Customer)
[00:26:14] got it

Richard H (Tutor)
[00:26:23]
[00:26:42] Now all that's left to do is use the calculator and find the exact answer

Guest (Customer)
[00:26:59] i got 13.40

Richard H (Tutor)
[00:27:06] Nice!

Guest (Customer)
[00:27:16]

Richard H (Tutor)
[00:27:19] But:
[00:27:58] remember that when we raise a number to the 2nd power, if it was negative or positive, the answer is still positive. So, when we take a square root, we usually put a plus-or-minus on what we get, since we don't know the original sign.
[00:28:48] Depending on the application, sometimes we want only positive numbers, but if we're not sure, we should use both

Guest (Customer)
[00:29:17] gotcha you expalined that better than my teacher lol

Richard H (Tutor)
[00:29:44] Glad I was able to make good sense then! To be sure, do you have any questions about anything we did here tonight?

Guest (Customer)
[00:30:14] nope got it all thank you!

Richard H (Tutor)
[00:30:36] No problem! For any other questions anytime, log in again! Please fill out the survey at the end, and have a nice night

Guest (Customer)
[00:30:58] alright goodnight

Richard H (Tutor)
[00:31:02] Bye