Question 337134
Find the exact value of sin165


it is not possible to find the exact value, even calculators will have rounding error, however you can use known sine values or sine values off a table to see if you are reasonably close, or just use the value off a calculator and round to the number of desired digits


0.258819 to 6 digits is the value of sin165 on my calculator



REVISITED PROBLEM


got a reply that said his/her book had these as choices:
a sqrt6 - sqrt2/4 
b sqrt6 + sqrt2/4 
c sqrt2 - sqrt6/4 
d sqrt:sqrt6 - sqrt2/4 


well choice d makes no sense unless
it is sqrt2 + sqrt6/4 
or sqrt(sqrt(6)) - sqrt2/4
or sqrt(sqrt(6) - sqrt2/4)


you could just use a calculator on all these and find out what is closest


sqrt(6) is 2.449490 to 6 places
sqrt(2) is 1.414214 to 6 places
sqrt(2)/4 is 0.353553 to 6 places
sqrt(6)/4 is 0.612372 to 6 places
sqrt(sqrt(6)) is 1.565085 to 6 places
sqrt(sqrt(6) - sqrt2/4) is 1.447735 to 6 places
sqrt(6) - sqrt(2) is 1.035276 to 6 places
(sqrt(6) - sqrt(2))/4 is 0.258819 to 6 places, hey that appears to work



a sqrt6 - sqrt2/4 --> this one seems closest to that though it is written badly




0.258819 to 6 digits is the value of sin165 on my calculator