hp40g+.book Page 26 Friday, December 9, 2005 1:03 AM

NOTE: The variable VX is now set to N. Reset it to X by

pressing

(to display CAS MODES screen)

and change the INDEP VAR setting.

To check the result, we can say that:

 

 

ex – 1

1

 

 

lim ------------- =

 

 

x → 0

x

 

 

 

and that therefore:

 

 

 

2

 

 

 

 

 

--

 

 

 

 

lim

en – 1

=

1

 

 

-------------

 

 

n → +∞

2

 

 

 

 

 

--

 

 

 

 

 

n

 

 

 

or, simplifying:

 

 

 

 

 

2

 

 

 

lim

--

n = 2

 

 

en – 1⎟

 

 

n → +∞

 

 

If the limit L of un exists as n approaches + ∞ in the

 

inequalities in solution 2 above, we get:

 

 

3

7

 

 

 

 

-- ⋅ 2 ≤

L -- ⋅ 2

 

 

2

4

 

 

Part 2

1.

Show that for every x in [0,2]:

 

 

2x + 3

 

 

1

 

 

--------------

= 2 – -----------

 

 

x + 2

 

x + 2

 

2. Find the value of:

 

 

 

2 2x + 3

 

 

 

 

--------------

 

 

 

I = 0 x + 2 dx

 

3. Show that for every x in [0,2]:

 

 

x

2

 

 

 

 

--

--

 

 

 

 

1 ≤ en en

 

 

 

4.

Deduce that:

 

 

 

 

 

2

 

 

 

 

 

--

 

 

 

 

1 ≤ un en I

 

 

5.

Show that un is convergent and find its limit, L.

16-26

 

 

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