Posted by Melinda on Sunday, January 29, 2012 at 10:03pm.
Determine the exact value of cos 465 degrees
a) √3 + √2/2
b) √2 + √3√2/4
c)√2  √3√2/4
d)2+√2√3√2/4

Precalculus  Reiny, Sunday, January 29, 2012 at 10:10pm
cos 465°
= cos(105+360)°
= cos 105°
= cos(60+45)°
= cos60cos45  sin60sin45
=(1/2)(√2/2)  (√3/2)(√2/2)
= (√2  √6)/4

Precalculus  Reiny, Sunday, January 29, 2012 at 10:12pm
I think c) comes closest if you had typed it correctly as
(√2  √3√2)/4 which then is the same as mine

Precalculus  Melinda, Sunday, January 29, 2012 at 10:20pm
Ok, thank you!
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