Problem 41
Calculate the derivative of the following functions.
y = ⁴√(2x / (4x - 3))
Problem 41a
Velocity from position The graph of represents the position of an object moving along a line at time . <IMAGE>
a. Assume the velocity of the object is 0 when . For what other values of t is the velocity of the object zero?
Problem 41c
Velocity from position The graph of represents the position of an object moving along a line at time . <IMAGE>
c. Sketch a graph of the velocity function.
Problem 42
Calculate the derivative of the following functions.
y = cos4 θ + sin4 θ
Problem 42a
Derivatives and tangent lines
a. For the following functions and values of a, find f′(a).
f(x) = 1/3x-1; a= 2
Problem 42b
Fish length Assume the length L (in centimeters) of a particular species of fish after t years is modeled by the following graph. <IMAGE>
b. What does the derivative tell you about how this species of fish grows?
Problem 43
Derivative calculations Evaluate the derivative of the following functions at the given point.
f(t) = 1/t+1; a=1
Problem 44a
Use the definition of the derivative to determine d/dx (√ax+b), where a and b are constants.
Problem 45
Calculate the derivative of the following functions.
y = (2x6 - 3x3 + 3)25
Problem 46
Derivatives of products and quotients Find the derivative of the following functions by first expanding or simplifying the expression. Simplify your answers.
f(x) = (√x+1)(√x-1)
Problem 47
Calculate the derivative of the following functions.
y = (1 + 2 tan u)4.5
Problem 48
Reproduce the graph of f and then plot a graph of f' on the same axes. <IMAGE>
Problem 49
Derivatives of products and quotients Find the derivative of the following functions by first expanding or simplifying the expression. Simplify your answers.
f(w) = w³-w/w
Problem 49b
The position (in meters) of a marble, given an initial velocity and rolling up a long incline, is given by s = 100t / t+1, where t is measured in seconds and s=0 is the starting point.
b. Find the velocity function for the marble.
Problem 50
Calculate the derivative of the following functions.
g(x) = x / e3x
Problem 51a
{Use of Tech} A different interpretation of marginal cost Suppose a large company makes 25,000 gadgets per year in batches of x items at a time. After analyzing setup costs to produce each batch and taking into account storage costs, planners have determined that the total cost C(x) of producing 25,000 gadgets in batches of x items at a time is given by C(x) = 1,250,000+125,000,000 / x + 1.5x.
a. Determine the marginal cost and average cost functions. Graph and interpret these functions.
Problem 52a
An angler hooks a trout and begins turning her circular reel at 1.5 rev/s. Assume the radius of the reel (and the fishing line on it) is 2 inches.
a. Let R equal the number of revolutions the angler has turned her reel and suppose L is the amount of line that she has reeled in. Find an equation for L as a function of R.
Problem 53
Calculate the derivative of the following functions.
y = sin(sin(ex))
Problem 53a
Where is the function continuous? Differentiable? Use the graph of f in the figure to do the following. <IMAGE>
a. Find the values of x in (0, 3) at which f is not continuous.
Problem 53b
Where is the function continuous? Differentiable? Use the graph of f in the figure to do the following. <IMAGE>
b. Find the values of x in (0, 3) at which f is not differentiable.
Problem 53c
Where is the function continuous? Differentiable? Use the graph of f in the figure to do the following. <IMAGE>
c. Sketch a graph of f'.
Problem 54
Robert Boyle (1627–1691) found that for a given quantity of gas at a constant temperature, the pressure P (in kPa) and volume V of the gas (in m³) are accurately approximated by the equation V=k/P, where k>0 is constant. Suppose the volume of an expanding gas is increasing at a rate of 0.15 m³/min when the volume V=0.5 m³ and the pressure is P=50 kPa. At what rate is pressure changing at this moment?
Problem 55
Evaluate and simplify y'.
x = cos (x−y)
Problem 55a
A capacitor is a device in an electrical circuit that stores charge. In one particular circuit, the charge on the capacitor Q varies in time as shown in the figure. <IMAGE>
a. At what time is the rate of change of the charge Q' the greatest?
Problem 55b
A capacitor is a device in an electrical circuit that stores charge. In one particular circuit, the charge on the capacitor Q varies in time as shown in the figure. <IMAGE>
b. Is Q′ positive or negative for t≥0?
Problem 55d
An object oscillates along a vertical line, and its position in centimeters is given by y(t)=30(sint - 1), where t ≥ 0 is measured in seconds and y is positive in the upward direction.
At what times and positions is the velocity zero?
Problem 55f
An object oscillates along a vertical line, and its position in centimeters is given by y(t) = 30(sin t - 1), where t ≥ 0 is measured in seconds and y is positive in the upward direction.
The acceleration of the oscillator is a(t) = v′(t). Find and graph the acceleration function.
Problem 56
Calculate the derivative of the following functions.
y = cos7/4(4x3)
Problem 56a
The energy (in joules) released by an earthquake of magnitude M is given by the equation E = 25,000 ⋅ 101.5M. (This equation can be solved for M to define the magnitude of a given earthquake; it is a refinement of the original Richter scale created by Charles Richter in 1935.)
Compute the energy released by earthquakes of magnitude 1, 2, 3, 4, and 5. Plot the points on a graph and join them with a smooth curve.
Problem 56b
Power and energy are often used interchangeably, but they are quite different. Energy is what makes matter move or heat up. It is measured in units of joules or Calories, where 1 Cal=4184 J. One hour of walking consumes roughly 10⁶J, or 240 Cal. On the other hand, power is the rate at which energy is used, which is measured in watts, where 1 W = 1 J/s. Other useful units of power are kilowatts (1 kW=10³ W) and megawatts (1 MW=10⁶ W). If energy is used at a rate of 1 kW for one hour, the total amount of energy used is 1 kilowatt-hour (1 kWh = 3.6×10⁶ J) Suppose the cumulative energy used in a large building over a 24-hr period is given by E(t)=100t + 4t² − (t³ / 9) kWh where t = 0 corresponds to midnight.
The power is the rate of energy consumption; that is, P(t) = E′(t) Find the power over the interval 0 ≤ t ≤ 24.
Ch. 3 - Derivatives
