Posted by Bill on Saturday, June 2, 2007 at 2:41pm.
Find the exact value of cos 300 degrees.
cos 300 = 1/2 = 0.500
how do you know? I am supposed to show my work.
You ought to know the rule on 30-60-90 triangles. If the hyp is 2, the shorter side is 1, and the longer side is sqrt3.
what does that have to do with cos300?
Cos(x) = Cos(-x) (1)
Cos(x + 360) = cos(x) (2)
Cos(300) = (using (2)) cos(-60) = (using (1)) cos(60) = using what Bobpursley wrote above 1/2
where did you get 60 from?
Bill, the sixty came from the addition formula above. 300 + 60 = 360
Bob, it says Cos(x + 360) .
Cos(x + 360) = Cos(x)
substitute x = y - 360:
Cos(y - 360 + 360) = Cos(y - 360) --->
Cos(y) = Cos(y - 360)
Substitute y = 300:
cos(300) = cos(-60)
Where did you get substitute x = y - 360 from? I'm sorry, I am so confused. Do you think you could give me the formula or whatever and then show me how to plug in the 300, or is that what you are doing now?
Answer This Question
More Related Questions
- Algebra 2 - find the exact value of cos 300 degrees.
- math - Determine exact value of cos(cos^-1(19 pi)). is this the cos (a+b)= cos a...
- Algebra II - Multiple Choice (theta) means the symbol 0 with the dash in it. 1.)...
- Trig - What is the exact value of cos 40 degrees cos 50 degrees minus sin 40 ...
- Algebra II - 1) Find the exact value of cos 105 degrees by using a half-angle ...
- trig - 2sin(x)cos(x)+cos(x)=0 I'm looking for exact value solutions in [0, 3...
- Trig hep, please? Thank you! - 1. Find the exact value of sin(195(degrees)) 2. ...
- Studying for Pre Cal exam - Find the fourth roots of − 1/2 + (square root)...
- math - If sin(x) = /45 and cos(y) = 5/13 with both x and y terminating in ...
- Math - If sin(x) = /45 and cos(y) = 5/13 with both x and y terminating in ...