PROBLEM
limx→0+(tanx⋅lnx)
STEP 1
1. We are dealing with a limit problem involving a product of two functions: tanx and lnx.
2. The limit is taken as x approaches 0 from the positive side, denoted by 0+.
3. The function lnx approaches −∞ as x approaches 0+, and tanx approaches 0.
STEP 2
1. Analyze the behavior of tanx and lnx as x→0+.
2. Use limit properties or transformations to evaluate the limit.
3. Conclude the result of the limit.
STEP 3
First, analyze the behavior of each function separately as x→0+.
- tanx approaches 0 as x approaches 0 from the positive side.
- lnx approaches −∞ as x approaches 0+.
STEP 4
Since the limit involves an indeterminate form 0⋅(−∞), we need to transform it into a form suitable for L'Hôpital's Rule or another method.
Rewrite the expression tanx⋅lnx as:
cotxlnx Now, as x→0+, lnx→−∞ and cotx→∞, resulting in the indeterminate form ∞−∞.
STEP 5
Apply L'Hôpital's Rule, which is applicable for indeterminate forms ∞∞ or 00.
Differentiate the numerator and the denominator:
- The derivative of lnx is x1.
- The derivative of cotx is −csc2x.
Apply L'Hôpital's Rule:
x→0+limcotxlnx=x→0+lim−csc2xx1 Simplify:
=x→0+limx−sin2x
STEP 6
Evaluate the limit:
As x→0+, sinx≈x, so sin2x≈x2.
x→0+limx−sin2x=x→0+limx−x2=x→0+lim−x=0
SOLUTION
Conclude the result of the limit:
The limit is:
0
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