NIMCET 2013 — Mathematics PYQ
NIMCET | Mathematics | 2013The value of x→0limx2tanxtanx−x is equal to:
Choose the correct answer:
- A.
0
- B.
1
- C.
21
- D.
31
(Correct Answer)
31
Explanation
Solution
We need to evaluate the limit:
Step 1: Simplify using standard limits
We know that as x→0, xtanx=1. To make use of this, we can multiply and divide the denominator by x:
Since x→0limxtanx=1, the expression simplifies to:
Step 2: Check for Indeterminate Form
Substituting x=0 into x3tanx−x gives 00−0=00. This is an indeterminate form.
Step 3: Solve using Expansion (Maclaurin Series)
The series expansion for tanx near x=0 is:
Substitute this into the limit:
Step 4: Evaluate the Limit
Divide every term by x3:
Explanation
Solution
We need to evaluate the limit:
Step 1: Simplify using standard limits
We know that as x→0, xtanx=1. To make use of this, we can multiply and divide the denominator by x:
Since x→0limxtanx=1, the expression simplifies to:
Step 2: Check for Indeterminate Form
Substituting x=0 into x3tanx−x gives 00−0=00. This is an indeterminate form.
Step 3: Solve using Expansion (Maclaurin Series)
The series expansion for tanx near x=0 is:
Substitute this into the limit:
Step 4: Evaluate the Limit
Divide every term by x3:
