Have i done my calculations from the tutorials right?

[rudimatt]

Hi,

Im a 31 year old computer programmer that want to revive some the calculus i learned at school, and learn new things as I go on. I seem to grasp things very fast as I remember while reading the tutorial here on the forum, but I need some help to check wether i have done those calculations right. I've read to lesson 6 for now and will continue if i get some answers of my questions here. Great tutorials by the way!

I wonder what the final answers in those examples are.

 

example lesson 5 (quotient rule):

: 6 / (x² + 16)

 

example lesson 6 (chain rule):

: 48x^8-33614

 

for number one exercise (in lesson 6) i get:

= 6x²+23

 

for number two exercise i get:

= 8x⁷+512x⁴+2048x³+131072

 

of course the first two examples are allready done by the tutorial except for the final answers.

i just wonder if these answers are right or if i am on a blueberry trip

 

link to the tutorials.

Edited April 9, 2013 by rudimatt

[tarimshahab]

All your answers are wrong, but not because of your derivation, but for the same mistake you make; probably because you were trying to do it quickly.

 

Specifically, generally speaking,

(x+a)^b IS NOT EQUAL TO x^b+a^b

 

So basically for the lesson 5 question: 6/(x+4)^2 doesn't simplify to 6/(x^2+16)

 

Same for the rest of your questions. Fix this, and I believe you'll get the right answer, since you don't make any other mistake.

 

 

BTW, if you want to quickly check if you got the right answer then the way to go is:

http://www.wolframalpha.com/

 

Just input "derive f(x)", you can derive and integrate and do a bunch of other stuff.

Edited July 31, 2014 by tarimshahab