SOLUTION: exact value of cos pi/12 cos pi/6

SOLUTION: exact value of cos pi/12 cos pi/6 - sin pi/12 sin pi/6

Question 969742: exact value of
cos pi/12 cos pi/6 - sin pi/12 sin pi/6
Answer by Edwin McCravy(20059) (Show Source): You can put this solution on YOUR website!

You need to know three things:

1. The formula you need is:



Substitute  for  and  for  in that
formula.

2. You need to know how to add the two fractions you'll have in the right side:

 by getting a common denominator of 12, and reduce it.

3. Finally you need to know the trig ratios for the special angles:

   |  p/6 |  p/4 | p/3  
----------------------      
sin|  1/2 | √2/2 |√3/2    
---|------|------|----
cos| √3/2 | √2/2 | 1/2

Good luck.  Need any more help?  If so, ask me in the thank-you note form below.
I'll get back to you.

Edwin

RELATED QUESTIONS
((cos(pi/4)+sin((pi/6))^2 (answered by greenestamps)

Find the exact value of sin pi/3 - cos... (answered by Alan3354)

sin(pi/6)+cos(pi/3)+cot(pi/6) (answered by Alan3354)

Find the exact value of the expression as a single fraction.... (answered by Alan3354)

Find the exact value of cos(pi) cos(3pi/4) + sin(pi) sin... (answered by jim_thompson5910,MathTherapy)

14. find the exact value of sin,cos,tan for this equation 7pi/12= pi/3+pi/4 (answered by Alan3354)

exact value of... (answered by jim_thompson5910)

Please simplify sin pi/12 times cos pi/12 Thanks (answered by MathLover1,Alan3354)

Sin... (answered by Edwin McCravy)