xlnjma aen±÷ - university of pittsburghkaveh/lecture-math0230-nov3-2017.pdf · nov. 3 / 2017 a ex...
TRANSCRIPT
Nov.
3 / 2017-
a
Ex ( From quiz )
an = tan ( 2in . 17 . +fg ) .
lim an = ?n → a
data'IIiIII÷s?
?
isno±±a⇒book at f ( × ) =
tan ( 2.gg# ) .
xlnjmaton (2@÷×) = tan ( ¥ ) ( continuity
Listen= * = ¥= '
.aEn±÷. Baoktoseniesconnergencetests
•
Alternatingseriesb, , bz , bz ,
- - - . bn 30
b,
- bz + b3 - by + bg . - - . - ?
E± bn =nt ( alt .
harmonic
I - ±+ } - 4- + . . .
corn.
series )
( harmonic
1++2+3 + . . - .
div. series )
-
Notation oo hit
b,
- bztb } - by + . . = [ f) bnn=l
C- 1 )"
-1 , +1,- 1
g^ - -
- .
nttna +1 , -1 , + 1 g- 1
, . --
H ) =tAH.seriestT.msleibintzb
, .bz/b3i - - -
�1� bn > ofor all n .
�2� b, 2 bzzbz - - - decreasing
�3� lim bn =D
n→
:Then [ C- IT "b,
=b,
- bztb }- by + . - .
.
n=1
is convergent @
¥ bn =h- D 1/+2 , } . - - > 0
�2� decreasing
�3� ntgmo'T =o
I - tztzt - ¥+ . - - converges(b) atttessefies) .
( Infact, we will see later using Taylor series
I - fist - It - - - = ln (2) ) .=mlificationofaltseniestest
#qblb
,
#b
,- bz
bz _•b3 b,
- bztb }bq•s- b,
- bztbz . by
-3g:
: :
:
If limit of alt . series !
-n
E*±§gH,2÷n- bn = End
lim -21 =- 2 1=0
n → a Itn
Se alt .series test does not
apply .
-
a hit�1� n3n÷ > 0
EI [Hnn3÷l@ lim nn÷t=°
n= I n→a
�3� dec . ?
f ( x ) =××z÷ - f{ × ) = 2×471-543×2=(113+1)2
=×(2-X] - × > 2 then flex )< 0 .
⇐3+42
( It is ok if decreasing starting from n=3 , . . )
-Absolwteconnengenucofaseriesja
, 1921 - - - an positive on negative .
Def § An is" absolutely convergent
"
if §|an|is convergent .
Ex= §4)"
+4 is convergent
but note absolutely convergent .
( §'T is div . ) .
. §an is"
conditionally Conn .
"
if
it is conu .but Lotabs
. Conn.
÷every If {lanl is conv
.then
§ an is Conn .
Or if abs.
Corn . => Conn . ( in usual Sense ) .
.
Next time : Ratio test .
TelRatio test ) ,
§ an
¥;z1an¥l=L< 1 then fanautos