Algebra II

posted by .

1)Find the exact value of sin 165 degrees.

2) Simplify: (4m/5n^2)- (n/2m)

Thanks

• Algebra II -

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

Similar Questions

1. Calculus

I had this on a test: Use the half-angle formula to find the exact value of the expresseion: sin 22.5 degrees my answer - 1/2 sqrt2 - sqrt 2 was wrong
2. 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 …
3. 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 = (21-16.8)^2 = 17.64...did that with the rest and …
4. Algebra II

Find the exact value of cos 375 degrees. Answer: (sqrt6 + sqrt2)/4 Is this correct?
5. Algebra II

Find the exact value of sin(theta/2) if cos theta = 2/3 and 270 degrees<theta<360 degrees. Answer: sqrt6/6
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^2-5n^3)/10n^2m Thanks