# Physics help

• August 28th 2008, 04:31 PM
Rainy2Day
Physics help
Hello there,

I dont even know where to start with this problem (Headbang) so I hope someone here can spare some time and help me (Happy)

1) Using your calculator verify that sin 0 divided by Cos 0 is equal to tan 0 for angle 0. Try 30 degrees and prove that this result is true in general by using the definitions for sin - and cos 0 and tan 0.

• August 28th 2008, 05:00 PM
skeeter
you can do the calculator verification, right?

definitions ...

$\cos{\theta} = \frac{x}{r}$
$\sin{\theta} = \frac{y}{r}$
$\tan{\theta} = \frac{y}{x}$

now, use the above definitions to show that
$\tan{\theta} = \frac{\sin{\theta}}{\cos{\theta}}$
• August 28th 2008, 05:19 PM
Rainy2Day
Umm how do you exactly do a calculator verification? (Worried)
• August 28th 2008, 05:31 PM
skeeter
what kind of calculator do you have?
• August 28th 2008, 05:44 PM
Rainy2Day
I got a ti-84 Plus not really sure how to use it though (Doh)
• August 28th 2008, 06:07 PM
skeeter
1. press the [MODE] button, move the dark blinking cursor on top of the word degree and press [ENTER].

2. go back to the home screen by pressing [2nd] [MODE].

3. enter the expression sin(0)/cos(0) then [ENTER] ... the calculator will return the value 0.

4. enter tan(0) and [ENTER] ... the calculator will return the same value 0.

5. Do the same operations with other angles ... 30 degrees, 52 degrees, whatever ... you'll see that the sin/cos calculation yield the same value as the tangent calculation. As such, you've verified that sin(x)/cos(x) = tan(x) with the calculator.
• August 28th 2008, 06:15 PM
Rainy2Day
Thank you for your help (Rofl)

It is much appreciated (Smirk)