Math Problem Statement

Using the definition, calculate the derivative of the function g(t) = 1/t^2. Then find the values of the derivative as specified at g'(-1), g'(2), g'(√3).

Solution

The given problem asks for the derivative of the function g(t)=1t2g(t) = \frac{1}{t^2} using the definition of the derivative. Additionally, we are asked to find the values of the derivative at specific points t=1t = -1, t=2t = 2, and t=3t = \sqrt{3}.

1. Finding the derivative using the definition

The definition of the derivative of a function g(t)g(t) is given by:

g(t)=limh0g(t+h)g(t)hg'(t) = \lim_{h \to 0} \frac{g(t+h) - g(t)}{h}

For the function g(t)=1t2g(t) = \frac{1}{t^2}, we apply this definition:

g(t)=limh01(t+h)21t2hg'(t) = \lim_{h \to 0} \frac{\frac{1}{(t+h)^2} - \frac{1}{t^2}}{h}

2. Simplification of the difference quotient

First, we simplify the numerator:

1(t+h)21t2=t2(t+h)2t2(t+h)2\frac{1}{(t+h)^2} - \frac{1}{t^2} = \frac{t^2 - (t+h)^2}{t^2(t+h)^2}

Expanding (t+h)2(t+h)^2 results in:

(t+h)2=t2+2th+h2(t+h)^2 = t^2 + 2th + h^2

Thus, the difference becomes:

t2(t2+2th+h2)=2thh2t^2 - (t^2 + 2th + h^2) = -2th - h^2

Now the difference quotient is:

g(t)=limh02thh2ht2(t+h)2g'(t) = \lim_{h \to 0} \frac{-2th - h^2}{h \cdot t^2(t+h)^2}

We can factor out hh from the numerator:

g(t)=limh0h(2th)ht2(t+h)2g'(t) = \lim_{h \to 0} \frac{h(-2t - h)}{h \cdot t^2(t+h)^2}

Canceling hh from the numerator and denominator:

g(t)=limh02tht2(t+h)2g'(t) = \lim_{h \to 0} \frac{-2t - h}{t^2(t+h)^2}

As h0h \to 0, this simplifies to:

g(t)=2tt4=2t3g'(t) = \frac{-2t}{t^4} = \frac{-2}{t^3}

Thus, the derivative of g(t)g(t) is:

g(t)=2t3g'(t) = \frac{-2}{t^3}

3. Finding the values of the derivative at specified points

Now we substitute the values t=1t = -1, t=2t = 2, and t=3t = \sqrt{3} into the derivative g(t)=2t3g'(t) = \frac{-2}{t^3}.

  • At t=1t = -1: g(1)=2(1)3=21=2g'(-1) = \frac{-2}{(-1)^3} = \frac{-2}{-1} = 2

  • At t=2t = 2: g(2)=223=28=14g'(2) = \frac{-2}{2^3} = \frac{-2}{8} = -\frac{1}{4}

  • At t=3t = \sqrt{3}: g(3)=2(3)3=233=239g'(\sqrt{3}) = \frac{-2}{(\sqrt{3})^3} = \frac{-2}{3\sqrt{3}} = \frac{-2\sqrt{3}}{9}

Final results:

  • g(1)=2g'(-1) = 2
  • g(2)=14g'(2) = -\frac{1}{4}
  • g(3)=239g'(\sqrt{3}) = \frac{-2\sqrt{3}}{9}

Let me know if you would like more details on any steps!

Relative questions:

  1. How is the definition of a derivative applied to other functions?
  2. What is the geometric interpretation of a derivative?
  3. Can we apply the product or chain rule instead for easier differentiation?
  4. How does the derivative change as tt approaches 0?
  5. How would the process differ if we had a higher degree polynomial?

Tip: Always simplify the difference quotient carefully, as errors in algebra can lead to incorrect results.

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Limits

Formulas

Definition of the derivative: g'(t) = lim(h→0) [(g(t+h) - g(t)) / h]
Simplification techniques for derivatives using algebra

Theorems

Limit definition of a derivative

Suitable Grade Level

Grades 11-12