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#1 2013-12-18 01:42:00

MERTICH
Member
Registered: 2013-12-01
Posts: 18

Squeeze Theorem

Use the squeeze theorem to determine

                                                                    LIM                                [ 3 -sin(e^x)]/                 3 minus Sin(exp x) divided by
                                                                   x--> infinity                     [V (X^2 + 2)]                   square root of ( x squared + 2)

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#2 2013-12-18 01:48:31

MERTICH
Member
Registered: 2013-12-01
Posts: 18

Re: Squeeze Theorem

I would also appreciate a stage by stage go...

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#3 2013-12-18 01:55:05

zetafunc.
Guest

Re: Squeeze Theorem

Use the fact that |sin(e[sup]x[/sup])| ≤ 1 and play with the inequality until you can bound your function.

#4 2013-12-18 02:03:29

MERTICH
Member
Registered: 2013-12-01
Posts: 18

Re: Squeeze Theorem

@ zetfunc , you mean like, since I know that no matter what, -1<sinx < 1 , so I should subsititute sin(e^x) with 1 and -1, in the expression to get my lower and upper bound?

Last edited by MERTICH (2013-12-18 02:10:09)

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#5 2013-12-18 02:11:44

zetafunc.
Guest

Re: Squeeze Theorem

The sine function, regardless of the argument (and as long as it is real), is always at least bounded between -1 and 1.

Do you see what we are trying to do?

#6 2013-12-18 02:29:37

MERTICH
Member
Registered: 2013-12-01
Posts: 18

Re: Squeeze Theorem

yes, but then how do you fit in the rest of the equation, or is it 2/( x^2 +2) </= f(x) </= 4/ (x^2 +2)  ?

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#7 2013-12-18 02:44:24

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 14,836

Re: Squeeze Theorem

Yes, that is correct. The limit of the left and right bound are easy to get, so you should be able to get the original limit now.


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

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#8 2013-12-18 03:08:23

zetafunc.
Guest

Re: Squeeze Theorem

Yes (with the square root signs).

Now you just need to show that the limits of both bounds go to zero as x approaches infinity.

#9 2013-12-18 04:02:47

MERTICH
Member
Registered: 2013-12-01
Posts: 18

Re: Squeeze Theorem

that is to say the denominator power of both bounds is greater than the numerator power, such that when x approaches infinity, f(x) becomes zero.....thank you guys!

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