# Math Help - Quick trig question

1. ## Quick trig question

Complete the following chart

y=cosx y=-cosx y=cos(-x)
domain
range
amplitude
period
x-intercept
y-intercept

Thank you!

2. Originally Posted by johett
Complete the following chart

y=cosx y=-cosx y=cos(-x)
domain
range
amplitude
period
x-intercept
y-intercept

Thank you!
You should be able to do the domain and range of these functions easily.

Otherwise
$y = A~cos(kx)$
is the (almost) most general form for the cosine function, where A is the amplitude. The period P of this function can be obtained by setting x = P:
$kP = 2 \pi \implies P = \frac{2 \pi}{k}$

The x intercept(s) should also be fairly easy. For what x values does cos(x) become 0?

For the y intercept simply input x = 0 into your equation.

-Dan

3. ## Please find exact value

$tan \frac{19\pi}{12}$
The correct answer is $-2-{\sqrt 3}$
$tan \frac{19\pi}{12}$
-tan 75=-tan (45 +30)=- $\frac{3+\sqrt 3}{3-\sqrt 3}$