SOLUTION: Hi, Thanks to whoever can solve this Evaluate the given expression show all work Express your answer as an exact value A) Sin 240 + Cos 120 B)2/sin^2 45° - 3/cos^2 30

Algebra ->  Trigonometry-basics -> SOLUTION: Hi, Thanks to whoever can solve this Evaluate the given expression show all work Express your answer as an exact value A) Sin 240 + Cos 120 B)2/sin^2 45° - 3/cos^2 30      Log On


   

Question 975996: Hi,
Thanks to whoever can solve this
Evaluate the given expression show all work Express your answer as an exact value
A) Sin 240 + Cos 120 B)2/sin^2 45° - 3/cos^2 30° C) Cos 30°tan 45°
Answer by anand429(138) About Me  (Show Source):
You can put this solution on YOUR website!
A.
sin(240) + cos (120)
= sin (180+60) + cos(90+30)
= -sin(60) -sin(30)
= -sqrt%283%29%2F2+-1%2F2
= +-%28%28sqrt%283%29%2B1%29%2F2%29
B.
2%2Fsin%5E2%2845%29+-+2%2Fcos%5E2%2830%29
= 2%2F%281%2F2%29+-+2%2F%283%2F4%29
=4-8/3
=4/3
C.
cos30 * tan 45
= %28sqrt%283%29%2F2%29+%2A+1