SOLUTION: cos 9pi/12 cos 3pi/12 + sin 9pi/12 sin 3pi/12

Algebra.Com
Question 1083978: cos 9pi/12 cos 3pi/12 + sin 9pi/12 sin 3pi/12
Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
cos 9pi/12 cos 3pi/12 + sin 9pi/12 sin 3pi/12
-------
cos(A-B) = cos(A)cos(B) + sin(A)sin(B)

RELATED QUESTIONS

Find exact value of cos 3pi/4 sin... (answered by lwsshak3)
Find the quotient of the complex numbers. Leave answer in polar form. z1 =... (answered by stanbon)
what is the value of cos... (answered by edjones)
Find the exact value of the expression cos(pi/12)cos(3pi/4) - sin(pi/12)sin(3pi/4) (answered by edjones)
Which of the following has no solution? A.Arc cos x=pi/12 B.Arc cos x=3pi/4 C.Arc... (answered by stanbon)
sin alpha = 3/5, pi/2 < alpha (answered by Fombitz)
Please help me solve this equation; I have to find the exact value of cos(13pi/12) I... (answered by stanbon,Alan3354)
sin theta= 12/13, 3pi/2 (answered by Edwin McCravy,feliz1965)
12) for x E[0,2pi), solve sin x = cos x a) pi/2 , 3pi/2 b) pi/4 (answered by jim_thompson5910)