Suppose two variables x and y are related by a given function y=f(x). If they both change with respect to a third variable (time, for instance), the rate of change of them is computed as the derivative using the chain rule:

$\displaystyle \frac{dy}{dt}=\frac{dy}{dx}\cdot \frac{dx}{dt}$

We have

$y=\sqrt{8+x^3}$

Or, equivalently

$y^2=8+x^3$

We need to know the rate of change of x respect to t. We'll use implicit differentiation:

$\displaystyle 2y\cdot \frac{dy}{dt}=3x^2\cdot \frac{dx}{dt}$

Solving for dx/dt

$\displaystyle \frac{dx}{dt}=\frac{2y\cdot \frac{dy}{dt}}{3x^2}$

Plugging in the values x=1, y=3, dy/dt=5

$\displaystyle \frac{dx}{dt}=\frac{2(3)\cdot 5}{3\cdot 1^2}=10$

The x-coordinate is changing at 10 cm/s

7 0

3 years ago

Three functions are given below: f(x), g(x), and h(x). Explain how to find the axis of symmetry for each function and rank the f

Anastaziya [24]

three functions are
f(x) = 3(x + 4)^2 + 1
g(x) = 2x^2 - 16x + 15
h(x) = a(x - 1) - 3
Axis of symmetry for f(x) is x=-4 For g(x)
by taking the derivative
g'(x) = 4x - 16
= 4(x - 4)
Axis of symmetry for g(x) is x=4
Axis of symmetry for h(x) is x=1
hope it helps

3 0

4 years ago