The Student Room Group

improper integrals

they are both " no value " but i get values??

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Original post by ckfeister
they are both " no value " but i get values??


Top one is fine... the second one is wrong because c^4 diverges as c tends to infinity.
Reply 2
Original post by RDKGames
Top one is fine... the second one is wrong because c^4 diverges as c tends to infinity.


But wouldn't that leave 1/3?
Original post by ckfeister
But wouldn't that leave 1/3?


It did in first one... what’s your confusion???
Reply 4
Original post by RDKGames
It did in first one... what’s your confusion???


Is it because its 1/3 - infinty = no value?
Original post by ckfeister
Is it because its 1/3 - infinty = no value?


No, the first one does indeed converge to 1/3... and the -infinity was going to be my next point; your line “as a->-infinity, 1/a->-infinity” is dead wrong.
Reply 6
Original post by RDKGames
No, the first one does indeed converge to 1/3... and the -infinity was going to be my next point; your line “as a->-infinity, 1/a->-infinity” is dead wrong.


Yea noticed its undefined... And I meant the second one 1/4 - c^4/4 = no value due to 1/4 - infinity?
Original post by ckfeister
How so? And I meant the second one 1/4 - c^4/4 = no value due to 1/4 - infinity?


Then yes 1/4 - infinity is clearly not a number.

As for your wrong statement, its because you’re essentially saying that some fraction goes to infinity when its denominator goes to infinity, which is wrong
Reply 8
infinity plus or minus any real number will still be equal to infinity. And negative infinity plus or minus any real number will still be equal to negative infinity.
Reply 9
Original post by RDKGames
Then yes 1/4 - infinity is clearly not a number.

As for your wrong statement, its because you’re essentially saying that some fraction goes to infinity when its denominator goes to infinity, which is wrong


i editted the post after a few seconds and thx for helping

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