Concept:A function is continuous at
x=0 if
limx→0f(x)=f(0).
If the limit does not exist or is not equal to
f(0), the function is discontinuous at
x=0.
Explanation:Check the limit for each option and compare it with the given value of
f(0).
For Option A:
limx→0(1+x)x2=e2 and
f(0)=e2.
So Option A is continuous at
x=0.
For Option B:
limx→0(sinx−cosx)=sin0−cos0=−1 and
f(0)=−1.
So Option B is continuous at
x=0.
For Option C:
As
x→0+,
x1→∞, so
ex1→∞.
Thus,
limx→0+ex1+1ex1−1=1.
As
x→0−,
x1→−∞, so
ex1→0.
Thus,
limx→0−ex1+1ex1−1=0+10−1=−1.
Since right-hand limit and left-hand limit are not equal,
limx→0f(x) does not exist.
Hence Option C is discontinuous at
x=0.
For Option D:
Using standard limits,
e5x−e2x≈5x−2x=3x and
sin3x≈3x.
So,
limx→0sin3xe5x−e2x=1 and
f(0)=1.
So Option D is continuous at
x=0.
Answer:Option C