Trigonometry Examples

$f (x) = - 2 \log_{2} (x)$

Step 1

Find the asymptotes.

Tap for more steps...

Step 1.1

Set the argument of the logarithm equal to zero.

$x^{2} = 0$

Step 1.2

Solve for $x$ .

Tap for more steps...

Step 1.2.1

Take the specified root of both sides of the equation to eliminate the exponent on the left side.

$x = \pm \sqrt{0}$

Step 1.2.2

Simplify $\pm \sqrt{0}$ .

Tap for more steps...

Step 1.2.2.1

Rewrite $0$ as $0^{2}$ .

$x = \pm \sqrt{0^{2}}$

Step 1.2.2.2

Pull terms out from under the radical, assuming positive real numbers.

$x = \pm 0$

Step 1.2.2.3

Plus or minus $0$ is $0$ .

$x = 0$

Step 1.3

The vertical asymptote occurs at $x = 0$ .

Vertical Asymptote: $x = 0$

Step 2

Find the point at $x = 1$ .

Tap for more steps...

Step 2.1

Replace the variable $x$ with $1$ in the expression.

$f (1) = - 2 \log_{2} (1)$

Step 2.2

Simplify the result.

Tap for more steps...

Step 2.2.1

Logarithm base $2$ of $1$ is $0$ .

$f (1) = - 2 \cdot 0$

Step 2.2.2

Multiply $- 2$ by $0$ .

$f (1) = 0$

Step 2.2.3

The final answer is $0$ .

$0$

Step 2.3

Convert $0$ to decimal.

$y = 0$

Step 3

Find the point at $x = 2$ .

Tap for more steps...

Step 3.1

Replace the variable $x$ with $2$ in the expression.

$f (2) = - 2 \log_{2} (2)$

Step 3.2

Simplify the result.

Tap for more steps...

Step 3.2.1

Logarithm base $2$ of $2$ is $1$ .

$f (2) = - 2 \cdot 1$

Step 3.2.2

Multiply $- 2$ by $1$ .

$f (2) = - 2$

Step 3.2.3

The final answer is $- 2$ .

$- 2$

Step 3.3

Convert $- 2$ to decimal.

$y = - 2$

Step 4

Find the point at $x = 4$ .

Tap for more steps...

Step 4.1

Replace the variable $x$ with $4$ in the expression.

$f (4) = - 2 \log_{2} (4)$

Step 4.2

Simplify the result.

Tap for more steps...

Step 4.2.1

Logarithm base $2$ of $4$ is $2$ .

$f (4) = - 2 \cdot 2$

Step 4.2.2

Multiply $- 2$ by $2$ .

$f (4) = - 4$

Step 4.2.3

The final answer is $- 4$ .

$- 4$

Step 4.3

Convert $- 4$ to decimal.

$y = - 4$

Step 5

The log function can be graphed using the vertical asymptote at $x = 0$ and the points $(1, 0), (2, - 2), (4, - 4)$ .

Vertical Asymptote: $x = 0$

$\begin{array}{c} x & y \\ 1 & 0 \\ 2 & - 2 \\ 4 & - 4 \end{array}$

Step 6