The explanation is here. the rest of the questions must be do by yourself.
The diagram shows 2 different shapes ...........................................................................................
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Thanks in advance
Thanks in advance
2 answers:
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Given that 
, we have for 
the Taylor series expansion about 0 as
Replace
with 
, so that the series is equivalent to
and notice that
Recall that for
, we have
which means
Replace
and notice that
Recall that for
which means