Question #67981

2 Answers
Apr 21, 2017

#lim_(x -> 0) (e^(3x) - e^(x))/x = 2#
#lim_(x -> 0) (e^(3x) - ex)/x = oo#

Explanation:

If you didn't make a typo and you meant #lim_(x -> 0) (e^(3x) - ex)/x# Then there is nothing else to do but substitute: #(1-0)/0 -> oo#

If you meant #lim_(x -> 0) (e^(3x) - e^(x))/x# Then we have an indetermination #(1-1) / 0 = 0/0# And we can use Bernoulli l'Hospital:

#lim_(x -> 0) (e^(3x) - e^(x))/x = lim_(x -> 0) ((d/dx)(e^(3x) - e^(x)))/((d/dx)x) = lim_(x -> 0) (3e^(3x) - e^(x))/1 = 2#

Apr 21, 2017

#2.#

Explanation:

We use this Standard Form of Limit : #lim_(x to 0)(e^x-1)/x=1.#

This will help us evaluate the reqd. limit without L'Hospital's Rule.

Reqd. Limit#=lim_(x to 0)(e^(3x)-e^x)/x#

#=lim_(x to 0) {((e^x)(e^(2x)-1))/x}#

#={lim_(x to 0) e^x}[2{lim_((2x) to 0) (e^(2x)-1)/(2x)}]#

#=(e^0)[2{1}]#

#:." The Reqd. Lim.="2.#

Enjoy Maths.!