192k views
3 votes
If f(x)=arcsin(x), then

lim f(x)−f(12)/x−12
x→12 is:
a) 1
b) 0
c) Undefined
d) -1

User Kaigorodov
by
8.2k points

1 Answer

2 votes

Final answer:

The limit lim f(x)−f(12)/x−12 as x approaches 12 is c) undefined.

Step-by-step explanation:

To find the value of the given limit, let's first find f(12). Since f(x) = arcsin(x), we substitute 12 into the function:

f(12) = arcsin(12).

However, the range of the arcsin function is restricted to -π/2 to π/2. Therefore, f(12) is undefined.

Next, let's find the limit:

lim f(x)−f(12)/x−12 as x approaches 12.

We substitute x = 12 into the limit expression:

lim f(x)−f(12)/x−12 = lim f(12)−f(12)/12−12 = lim 0/0.

Since we have a 0/0 indeterminate form, we can use L'Hopital's Rule.

Differentiating f(x) with respect to x, we get f'(x) = 1/√(1-x^2).

Now we can apply L'Hopital's Rule again:

lim f(x)−f(12)/x−12 = lim (1/√(1-x^2))/(1-0) = lim (1/√(1-x^2)).

Substituting x = 12, we get

lim (1/√(1-(12)^2)) = lim (1/√(1-144)) = lim (1/√(-143)).

Since the square root of a negative number is undefined, the limit is also undefined.

User ChrisBratherton
by
8.4k points