can you do this?

[Dencology]

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guys how do you do this:

if sin(2teta)= 2sine[teta]cos[teta] then
(sine 15)(cos 15)= ?

a. 1/4
b. sqroot of 2/4
c. sqroot of 3/4
d. 1

please explain how you got your ans. thanks.

 

[happyasaclam88]

sin(15)cos(15) is then equal just to sin(2*15)/2 (the two is from the other side of the double angle formula). so that's sin(30)/2, or sin(pi/6)/2 is radians is more your thing.
sin(pi/6) is 1/2, over 2 is 1/4, so the answer is a. at least, i hope it is ...