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Precalculus JumpStart

Exercises 5.8 Exercises

1.

Is the given point on the graph of \(y^2 = x^3 - 10 x + 3\text{?}\) How can you be sure?
  1. \(\displaystyle (3,0)\)
  2. \(\displaystyle (0,3)\)
  3. \(\displaystyle (0,\sqrt{3})\)
  4. \(\displaystyle (\sqrt{3},0)\)
  5. \(\displaystyle (1,2)\)

2.

Find an equation for the circle having the points \((-2,4)\) and \((7,9)\) as endpoints of a diameter.

Linear Equations.

3.

Sketch a graph of each equation.
  1. \(\displaystyle x=-4\)
  2. \(\displaystyle y=3\)
  3. \(\displaystyle 2y=-1\)

4.

What is an equation for the \(x\)-axis? What is an equation for the \(y\)-axis?

5.

Find the intercepts of \(4x-7y = 2\) and sketch its graph.

6.

Sketch a graph of \(y - 7 = -2 (x+1)\)

7.

Find a linear equation for the line passing through the points \((5,4)\) and \((-2,3)\text{.}\)

8. Linear Models.

Let \(C\) denote the annual cost in millions of dollars to maintain a computer network \(t\) years since the year 2000 (so that \(t = 0\) corresponds to the year 2000). In 2005, it cost 2 million dollars and, in 2010 it cost 17 million dollars.
  1. At what rate is the cost increasing per year, assuming the rate of increase remains constant?
  2. Find a linear model for the cost \(C\text{.}\)
  3. Use your model to predict the cost to maintain the network in 2020.

9. A Parabola.

Find an equation for the parabola with focus at \(F(0,-1)\) and directrix \(y = 2\text{.}\)