Sequence And Series Question 352
Question: In the expansion of $ \frac{e^{5x}+e^{x}}{e^{3x}} $ , the coefficient of $ x^{4} $ is
Options:
A) - $ 6/5 $
B) 4/3
C) - 4/3
D) None of these
Show Answer
Answer:
Correct Answer: B
Solution:
$ \frac{e^{5x}+e^{x}}{e^{3x}}=e^{2x}+{e^{-2x}}=2{ 1+\frac{{{(2x)}^{2}}}{2\ !}+\frac{{{(2x)}^{4}}}{4\ !}+…… } $ Coefficient of $ x^{4}=2.\frac{2^{4}}{4\ !}=\frac{4}{3} $ .
BETA
