The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

C2 integration

when I'm doing definite integration and I am substituting in values, I have integrated and got to

2x^(1/2) + x between 9 and 4.

WHy do we only use the positive values of the square root? WHat happens with the negative square root?

Thanks!
Not sure if you're trolling or not but..

[br]x=1&−1[br]If[br]x2−1=0[br][br]x = 1 \& -1[br]If[br]x^2 - 1 = 0[br]
Contrary to
[br]1.5=1[br][br]1^{.5} = 1[br]
Reply 2
Avatar for TeeEm
TeeEm
19
Original post by jgt
when I'm doing definite integration and I am substituting in values, I have integrated and got to

2x^(1/2) + x between 9 and 4.

WHy do we only use the positive values of the square root? WHat happens with the negative square root?

Thanks!


http://www.thestudentroom.co.uk/showthread.php?t=3173187
Reply 3
Avatar for Zacken
Zacken
22
Original post by jgt
when I'm doing definite integration and I am substituting in values, I have integrated and got to

2x^(1/2) + x between 9 and 4.

WHy do we only use the positive values of the square root? WHat happens with the negative square root?

Thanks!


x≥0\sqrt{x} \geq 0.
Original post by jgt
when I'm doing definite integration and I am substituting in values, I have integrated and got to

2x^(1/2) + x between 9 and 4.

WHy do we only use the positive values of the square root? WHat happens with the negative square root?

Thanks!


What difference does it make anyway?

From here, simply insert 9 into the integrated function and subtract F(4) from it.
ie. 15 - 8 = 7, which is the answer here, irrespective of positive or negative values of radicals!
Reply 5
Avatar for Zacken
Zacken
22
Original post by Bath_Student
What difference does it make anyway?


Because it would be wrong.

From here, simply insert 9 into the integrated function and subtract F(4) from it.
ie. 15 - 8 = 7, which is the answer here, irrespective of positive or negative values of radicals!


...this makes zero sense in context as to the inquiry of the OP.
Original post by Zacken
Because it would be wrong.



...this makes zero sense in context as to the inquiry of the OP.


Shut the f up
Original post by GeologyMaths
Shut the f up


That's the spirit!

I can tell a fellow chemical engineer when I see one :smile:
Original post by Bath_Student
That's the spirit!

I can tell a fellow chemical engineer when I see one :smile:

:wink:

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you