Series 365
For problems 6–8, determine whether each
series converges absolutely, converges
conditionally, or diverges.
6.
∑∞
n= 1
(−1)n−^1
n!
7.
∑∞
n= 1
(−1)n−^1
n+ 1
n
8.
∑∞
n= 1
(−1)n
n+ 1
7 n^2 − 5
- Find the sum of the geometric series
∑∞
n= 0
4
(
1
3
)n
.
- If the sum of the alternating series
∑∞
n= 1
(−1)n−^1
2 n− 1
is approximated bys 50 , find the
maximum absolute error.
Find the interval of convergence for each series.
∑∞
n= 0
xn
1 +n^2
- ∑∞
n= 1
3 n
n^2
xn
- The Taylor series representation of lnx,
centered atx=a.
Approximate each function with a fourth
degree Taylor polynomial centered at the given
value ofx.
- f(x)=ex^2 atx= 1.
- f(x)=cosπxatx=
1
2
.
- f(x)=lnxatx=e.
Find the MacLaurin series for each function and
determine its interval of convergence.
- f(x)=
1
1 −x
- f(x)=
1
1 +x^2
- Estimate sin 9◦accurate to three decimal
places. - Find the rational number equivalent to
1 .83.
14.10 Cumulative Review Problems
- The movement of an object in the plane is
defined byx(t)=lnt,y(t)=t^2. Find the
speed of the object at the moment when
the acceleration isa(t)=〈−1, 2〉. - Find the slope of the tangent line to the
curver=5 cos 3θwhenθ=
2 π
3
.
23.
∫e
1
x^3 lnxdx
24.
∫ 1
0
5
x^2 −x− 6
dx
- limx→ 1
lnx
x^2 − 1
14.11 Solutions to Practice Problems
1.
∑∞
n= 0
5 −n=
∑ 1
5 n
= 1 +
1
5
+
1
25
+
1
125
+···is a geometric series with an initial
term of one and a ratio of
1
5
. Since the
ratio is less than one, the series converges,
and
∑∞
n= 0
5 −n=