Recognize Limit Problem: Recognize the limit problem and apply L'Hôpital's Rule if necessary.Since the limit is of the form 0/0, we can apply L'Hôpital's Rule, which states that if the limit of f(x)/g(x) as x approaches a value c is of the form 0/0 or ±∞/±∞, then the limit is the same as the limit of f′(x)/g′(x) as x approaches c, provided that this latter limit exists.
Differentiate Numerator and Denominator: Differentiate the numerator and denominator separately.The derivative of the numerator tan(2x)−sin(2x) with respect to x is sec2(2x)⋅2−cos(2x)⋅2.The derivative of the denominator x3 with respect to x is 3x2.
Apply L'Hôpital's Rule Once: Apply L'Hôpital's Rule once.We now have the new limit as x approaches 0 of (2⋅sec2(2x)−2⋅cos(2x))/(3x2).
Evaluate New Limit: Evaluate the new limit as x approaches 0. As x approaches 0, sec2(2x) approaches sec2(0) which is 1, and cos(2x) approaches cos(0) which is also 1. So, the limit becomes 00 which simplifies to 01, indicating that we need to apply L'Hôpital's Rule again.
Differentiate Again: Differentiate the new numerator and denominator again.The derivative of the new numerator 2sec2(2x)−2cos(2x) with respect to x is 2⋅2⋅sec2(2x)⋅tan(2x)⋅2−2⋅(−sin(2x)⋅2).The derivative of the new denominator 3x2 with respect to x is 6x.
Apply L'Hôpital's Rule Second Time: Apply L'Hôpital's Rule a second time.We now have the new limit as x approaches 0 of (8⋅sec2(2x)⋅tan(2x)−4⋅sin(2x))/6x.
Evaluate New Limit: Evaluate the new limit as x approaches 0. As x approaches 0, sec2(2x) approaches 1, tan(2x) approaches 0, and sin(2x) approaches 0. So, the limit becomes 00 which simplifies to 01, indicating that we need to apply L'Hôpital's Rule yet again.
Differentiate Again: Differentiate the new numerator and denominator again.The derivative of the new numerator 8sec2(2x)tan(2x)−4sin(2x) with respect to x is 8(2sec2(2x)tan(2x)⋅2+2sec2(2x)sec2(2x)⋅2)−4(cos(2x)⋅2).The derivative of the new denominator 6x with respect to x is 6.
Evaluate New Limit: Evaluate the new limit as x approaches 0. As x approaches 0, sec2(2x) approaches 1, tan(2x) approaches 0, and cos(2x) approaches 1. So, the limit becomes 00 which simplifies to 01 which further simplifies to 02.
Simplify Final Answer: Simplify the result to find the final answer.The final answer is (16−8)/6 which simplifies to 8/6, and further simplifies to 4/3.
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