Monday

November 24, 2014

November 24, 2014

Posted by **Haley** on Wednesday, November 28, 2012 at 9:47pm.

1) cos(345°)

- pre-calc help !!!!!!! -
**Reiny**, Wednesday, November 28, 2012 at 10:22pmdid you notice that 345 = 360-15 ?

cos(345)

= cos15

cos15 = cos(45-30)

= cos45cos30 + sin45sin30

= (√2/2)(√3/2) + (√2/2)(1/2)

= ( √6 + √2)/4

cos 345 = (√6+√2)/4

**Answer this Question**

**Related Questions**

Pre-Calc - Could someone show me how to solve these two problems-I have 10 of ...

Math, Pre-Calc - the original problem was: Solve: sin(3x)-sin(x)=cos(2x) so far ...

pre-calc - Solve: cos(2x-180) - sin(x-90)=0 my work: cos2xcos180 + sin2xsin180= ...

Calculus - Seperable Equations - Solve the separable differential equation (dy/...

pre-calc help !!!!!!! - #1 cos x+sec x=2 #2 (1+tan x)^2= 2 tan x+2 #3 cos^2x-sin...

pre-calc helpppp - Find sin x/2, cos x/2, and tan x/2 from the given information...

Pre Calculus - Can someone help me solve this problem: cos^2x + 5cosx - 2= 0 I ...

Pre-Calc - I have two questions how do you solve cos x=sqrt2-cosx on the ...

Pre-Calc - Evaluate the expression without using a calculator(show work please...

Pre Calculus Repost Please Help - Can someone help me solve this problem: cos^2x...