#lim_(n->oo)root(n)(n^2 (sqrt[2])^n + (pi/2)^n + 3 (3/2)^n) = # ?

1 Answer
Jan 20, 2018

#pi/2#

Explanation:

We have

#sqrt2 < 1.5 < pi/2 # then

#root(n)(n^2 (sqrt[2])^n + (pi/2)^n + 3 (3/2)^n) = pi/2 root(n)((2sqrt[2]/pi)^n n^2+ 1 + 3 (3/2 2/pi)^n) #

here

#2sqrt[2]/pi < 1#
#3/pi < 1#

then

#lim_(n->oo)root(n)(n^2 (sqrt[2])^n + (pi/2)^n + 3 (3/2)^n) = #

#=pi/2 root(n)(lim_(n->oo)(2sqrt[2]/pi)^n n^2+ 1 + 3 lim_(n->oo)(3/pi)^n) = pi/2#

because

#lim_(n->oo)(2sqrt[2]/pi)^n n^2=0#
#lim_(n->oo)(3/pi)^n = 0#