NIMCET 2023 — Mathematics PYQ
NIMCET | Mathematics | 2023lf is a real number then

lf f(x)=limx→0loge9(1−cosx)6x−3x−2x+1 is a real number then limx→0f(x)
2
3
Loge2
(Correct Answer)Loge3
Loge2
Evaluating the Limit of f(x)
The limit of f(x) as x→0 is to be evaluated.
Step 1: Simplify the numerator
The numerator, 6x−3x−2x+1, can be factored. It is observed that 6x−3x−2x+1=3x2x−3x−2x+1=3x(2x−1)−1(2x−1)=(3x−1)(2x−1).
Step 2: Apply standard limits
The limit of the expression can be rewritten using standard limit forms. The expression becomes limx→0loge9(1−cosx)(3x−1)(2x−1). This can be rearranged as limx→0x(3x−1)⋅x(2x−1)⋅(1−cosx)x2⋅loge91. It is known that limx→0xax−1=logea and limx→0x21−cosx=21.
Step 3: Substitute the standard limits
Substituting the known limits into the expression: The limit is equal to (loge3)⋅(loge2)⋅211⋅loge91. This simplifies to 2⋅loge9(loge3)(loge2).
Step 4: Simplify the logarithmic terms
Using the property of logarithms logeab=blogea, it is known that loge9=loge32=2loge3. Substituting this into the expression: The limit becomes 2⋅2loge3(loge3)(loge2).
Step 5: Calculate the final value
The term 2loge3 in the denominator cancels with 2 and loge3 in the numerator. The final value of the limit is loge2.
Final Answer
The value of limx→0f(x) is loge2.
Evaluating the Limit of f(x)
The limit of f(x) as x→0 is to be evaluated.
Step 1: Simplify the numerator
The numerator, 6x−3x−2x+1, can be factored. It is observed that 6x−3x−2x+1=3x2x−3x−2x+1=3x(2x−1)−1(2x−1)=(3x−1)(2x−1).
Step 2: Apply standard limits
The limit of the expression can be rewritten using standard limit forms. The expression becomes limx→0loge9(1−cosx)(3x−1)(2x−1). This can be rearranged as limx→0x(3x−1)⋅x(2x−1)⋅(1−cosx)x2⋅loge91. It is known that limx→0xax−1=logea and limx→0x21−cosx=21.
Step 3: Substitute the standard limits
Substituting the known limits into the expression: The limit is equal to (loge3)⋅(loge2)⋅211⋅loge91. This simplifies to 2⋅loge9(loge3)(loge2).
Step 4: Simplify the logarithmic terms
Using the property of logarithms logeab=blogea, it is known that loge9=loge32=2loge3. Substituting this into the expression: The limit becomes 2⋅2loge3(loge3)(loge2).
Step 5: Calculate the final value
The term 2loge3 in the denominator cancels with 2 and loge3 in the numerator. The final value of the limit is loge2.
Final Answer
The value of limx→0f(x) is loge2.
