Algebra II
posted by Lucy .
1)Find the exact value of sin 165 degrees.
Answer: (sqrt6 + sqrt2)/4
2) Simplify: (4m/5n^2) (n/2m)
Answer: (8m^25n^3)/10n^2m
Thanks

Algebra II 
Reiny
The answer they gave you for the first one is not correct.
Here is the right way:
sin 165
= sin(120+45)
= sin120cos45 + cos120sin45
= sin60sin45 + (cos60sin45)
= (√3/2)(√2/2)  (1/2)(√2/2)
= (√6  √2)/4
(my answer checked with calculator)
Respond to this Question
Similar Questions

Calculus
I had this on a test: Use the halfangle formula to find the exact value of the expresseion: sin 22.5 degrees my answer  1/2 sqrt2  sqrt 2 was wrong 
Algebra
1)A bookshelf holds 4 mysteries, 3 biograpghies, 1 book of poetry, and 2 reference books. If a book is selected at random from the shelf, find the probability that the book selected is a biography or reference book. A)1/2 B)1/6 C)5/6 … 
Math
1)Find the standard deviation of the data set to the nearest tenth. (21,13,18,16,13,35,12,8,15) A)16.8 B)7.8 C)7.3 D)5.7 I chose C mean = 21+13+18+16+13+35+12+8+15/9 16.8 variance = (2116.8)^2 = 17.64...did that with the rest and … 
Algebra II
Find the exact value of cos 375 degrees. Answer: (sqrt6 + sqrt2)/4 Is this correct? 
Algebra II
Find the exact value of sin(theta/2) if cos theta = 2/3 and 270 degrees<theta<360 degrees. Answer: sqrt6/6 
Algebra II
1)Find the exact value of sin 165 degrees. Answer: (sqrt6 + sqrt2)/4 2) Simplify: (4m/5n^2) (n/2m) Answer: (8m^25n^3)/10n^2m Thanks 
PreCalculuscheck answers
Use a sum or difference identity to find the exact value of sin 255 degrees Answer: sqrt6sqrt2/4 Thanks 
Trigonometry
Find the exact value of tan(ab) sin a = 4/5, 3pi/2<a<pi; tan b = sqrt2, pi/2<b<pi identity used is: tan(ab)=(tan atan b)/1+tan a tan b simplify answer using radicals. (a is alpha, b is beta) 
Math Answer Check
1. Find the exact value of the expression. cos pi/16 * cos 3pi/16  sin pi/16 * sin 3pi/16 My ans: sqrt2/2 2. Find the exact value of the sin of the angle. 17pi/12 = 7pi/6 + pi/4 My ans: (sqrt2  sqrt6)/4 
PreCalc
Find the exact value of sin345 degrees using a sum or difference formula. I got (sqrt6 + sqrt2)/4. Is this right?