Thursday, December 23, 2010

inkorrect.

"That's not right."

Unfortunately, JM, that's not the solution they give in the book.

It is:

[X . sqrt(X + 1) + 2 . (X + 1)] / 2 . (X + 1)

I don't get how that's right. But the book has to be right.

Hoping I'll understand next year.

3 comments:

Harvard said...

Hey, you can do pentatonic improvisation, right? Because I need you to pentatonic-improv while wearing a fedora and being all new-orleans-y for http://www.youtube.com/watch?v=7jvpl9Y9gSo&feature=related . Disregard if you think this is a bad idea.

JM said...

Sorry, I made an error. It's ^1/2, not ^2.

But my final answer is:
x/2(x+1)^1/2 + (x+1)^1/2

If you continue to simplify into a single fraction, it will equal to:
[x+2(x+1)]/[2(x+1)^1/2]
= [3x+2]/[2(x+1)^1/2]

Check it here: http://www.numberempire.com/derivatives.php

NOW if you keep continuing to make the denominator 2(x+1), you get:
[(3x+2)(x+1)^1/2]/[2(x+1)]

I'm quite certain this is right, UNLESS I interpreted the question wrong. It is, differentiate x*(x+1)^1/2, right?

JM said...

Okay, I just published this comment but it's not showing and now I'm getting annoyed at blogspot. Just saying that textbooks don't always need to be right. I'm sure there are a handfull of errors in the answers section.

Now I'm not sure if my first comment went through so here is what I said:
Oops I made this mistake and my final answer is x/[2(x+1)^1/2] + (x+1)^1/2

If you continued with this answer, you would get (3x+2)/[2(x+1)^1/2] (all in a single fraction). And if you continued further, it would be [(3x+2)*(x+1)^1/2]/[2(x+1)]

Check http://www.numberempire.com/derivatives.php It returns the same answer as above.