circular functions

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March 11th 2011, 02:49 PM
stuckonmath

circular functions

I'm working on a homework assignment for class and I'm really stuck on one. The answers are in the back of the book so I know I'm doing it wrong but I can't figure out where. Thanks!

evaluate the given expression, leaving the answer in simple radical form. (sec 30)/(cos 30) I keep getting 1 i don't know why.
March 11th 2011, 02:53 PM
e^(i*pi)

Wrong answer - see post 5
March 11th 2011, 02:57 PM
stuckonmath

so i was right? bc the book says 4/3
March 11th 2011, 02:59 PM
Plato

Quote:

Originally Posted by stuckonmath

(sec 30)/(cos 30) I keep getting 1 i don't know why.

Because $\sec(30)=\dfrac{1}{\cos(30)}$ we get $\dfrac{\sec(30)}{\cos(30)}=\dfrac{1}{\cos^2(30)}.$
March 11th 2011, 03:02 PM
stuckonmath

so i was wrong? what you're saying makes sense but why doesn't it work out when i it the normal way?
March 11th 2011, 03:09 PM
Plato

Quote:

Originally Posted by stuckonmath

so i was wrong? what you're saying makes sense but why doesn't it work out when i it the normal way?

What does the normal way mean?
March 11th 2011, 03:12 PM
stuckonmath

haha sorry i usually figure out what what they are as is. so sec 30 would be (2 square route 3)/3 and cos 30 is square route of 3/2
March 12th 2011, 05:18 AM
e^(i*pi)

Yes, so you now have $\dfrac{\frac{2\sqrt3}{3}}{\frac{\sqrt{3}}{2}} = \dfrac{2\sqrt3}{3} \times \dfrac{2}{\sqrt3}$
March 12th 2011, 02:22 PM
HallsofIvy

You titled this "circular functions" so it seems very strange that you would deal with degrees. In the definition of "circular functions" is not an angle at all- it is a distance around the circumference of the circle. And if you want to interpret it as an angle, you have to set it in radians- the distance around the entire circle of radius 1 is $2\pi$ .

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