You can put this solution on YOUR website! Use the cosine angle addition formula. cos(165°) = cos(120° + 45°)

Feb 16, 2017 · How do you use the sum or difference identities to find the exact value of #cos165^circ#?

Feb 25, 2017 · tan (-165) = (sqrt(2 - sqrt3))/(sqrt(2 + sqrt3) sin (-165) = sin (195) --> co-terminal. Call sin (195) = sin t Use trig table and unit circle: cos 2t = cos 390 = cos (30 + 360) = cos 30 = sqrt3/2 Use trig identity: 2sin^2 t = 1 - cos 2t 2sin^2 t = 1 - sqrt3/2 = (2 - sqrt3)/2 sin^2 t = (2 - sqrt3)/4 sin t = +- (2 - sqrt3)/2 Since sin (- 165) is negative, then, take the negative answer. sin ...

Question 1159668: Use half-angle formulas to find the exact values. cos 165° I got /2 which is wrong. This is my work:

cos 165 = - sqrt(2 + sqrt3)/2 Use half angle identity: cos (a/2) = +- sqrt((1 + cos a)/2) In this case, cos (a/2) = cos 165, and cos a = cos 330. Trig table gives ...

Aug 9, 2015 · Find sec ((-11pi)/12) Ans: - 4/(sqrt2 + sqrt6) sec = 1/cos cos ((-11pi)/12) = cos ((11pi)/12) = cos ((3pi)/12 + (8pi)/12) = = cos (pi/4 + (2pi)/3) Use the trig ...

May 4, 2015 · 180^o = pi " radians" 165^o = 165^o * (pi " radians")/(180^o) = 2.88 " radians" (approx.)

How do you write the trigonometric form into a complex number in standard form #3(cos 165.5+isin165.5)#? Trigonometry The Polar System The Trigonometric Form of Complex Numbers 2 Answers

Question 849128: Find the exact value using a sum or difference identity. cos(165°) Answer by stanbon(75887) ( Show Source ): You can put this solution on YOUR website!

You can put this solution on YOUR website! find the exact value of the expression sin 165 degrees. ** sin (x+y)=sinxcosy+cosxsiny