The value of cos 70° + cos 50°
cos 70° + cos 50º – cos 10° is​

1 thought on “The value of cos 70° + cos 50°<br />cos 70° + cos 50º – cos 10° is​”

1. Step-by-step explanation:

   sin(0) 0, cos(0) 1, tan(0) 0

   sin(90) 1, cos(90) 0, tan(90)

   sin(180) 0, cos(180) 1, tan(180) 0

   sin(270) 1, cos(270) 0, tan(270)

   1 3 3 sin(30) cos(60) , cos(30) sin(60) , tan(30) , tan(60

   2 2 3

   = = =

   = = = ∞

   = = − =

   = − = = −∞

   = = = = = ) 3

   2

   sin(45) cos(45) , tan(45) 1

   2

   =

   = = =

   2 2

   Law of sines:

   sin sin sin

   Law of cosines: 2 cos

   abc

   c a b ab

   abg

   g

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