Problem 7 - College Algebra and Calculus: An Applied Approach

Question

In Exercises, find the second derivative of the function. $$ f(t)=\frac{3}{4 t^{2}} $$

Step-by-Step Solution

Answer

The second derivative of the function \(f(t)\) = \(\frac{3} {4t^{2}}\) is \(f''(t) = \frac{9} {2t^{4}}\).

Step 1: Find the first derivative

To find the first derivative of \(f(t)\), we will use the power rule of differentiation, which states that the derivative of \(t^n\) is \(n*t^{n-1}\). Applying this rule to \(f(t)\), we get \(f'(t) = \frac{d}{dt}(\frac{3} {4t^{2}}) = \frac{-3}{2t^{3}}\).

Step 2: Find the second derivative

Now we need to find the second derivative of \(f(t)\), which is the derivative of \(f'(t)\). Again, we apply the power rule to get \(f''(t) = \frac{d}{dt}(\frac{-3}{2t^{3}}) = \frac{9}{2t^{4}}\).

Key Concepts

Power Rule Differentiation

Understanding Power Rule Differentiation is a cornerstone of calculus, particularly when dealing with polynomial functions. It simply states that for any function in the form of t^n, where n is a real number, its derivative is given by n \times t^{(n-1)}. Let's consider an example where we have f(t) = t^5. Differentiating it would involve bringing the exponent down as a coefficient and subtracting one from the exponent, resulting in f'(t) = 5t^4.

In the exercise provided, we applied the power rule to f(t) = \(\frac{3}{4 t^{2}}\), which is the same as f(t) = 3t^{-2}/4. The -2 comes down to multiply the three, creating a coefficient of -3/2, and the exponent increases to -3 to give f'(t) = \(\frac{-3}{2t^{3}}\). The power rule is a quick and reliable method to find derivatives of power functions and is an essential tool for more complex calculus problems involving first and higher-order derivatives.

First Derivative

The First Derivative of a function is a profound concept in calculus, representing the rate at which the function's value changes at any given point. It's essentially the slope of the tangent line to the function's graph at that point. In practical terms, this derivative can tell us the velocity if our function represents the position of an object over time.

When we calculated the first derivative of the function f(t) = \(\frac{3}{4 t^{2}}\), we were seeking to understand how the function's output changes as t changes. The resulting first derivative f'(t) = \(\frac{-3}{2t^{3}}\), tells us that the slope of our function is negative and that the rate of change becomes less negative as t gets larger, due to the negative cubic relationship. Remember, whenever you're looking at the first derivative, you're essentially exploring the instantaneous rate of change of the function at any given point.

Higher-Order Derivatives

Delving into Higher-Order Derivatives, we move beyond the first derivative to explore how the rate of change itself changes. The second derivative, which we obtained in the exercise, is a notable example. It can tell us about the curvature or concavity of the function's graph and is used to identify maxima and minima -- critical points that are highly valuable in many scientific and economic contexts.

The second derivative we calculated, f''(t) = \(\frac{9}{2t^{4}}\), is the derivative of the first derivative. In physical terms, if our function described the position of an object, the second derivative would represent the object's acceleration. In this case, the positive value of the second derivative suggests that the rate of change of our rate of change is positive, meaning the function is concave up and that as t grows, the original function's rate of decrease is slowing down.