Jul 30, 2016 · #(2pi)/3 "is an angle in the " color(blue)"2nd quadrant where the cos ratio is negatve"# #rArrcos((2pi)/3)=-cos(pi-(2pi)/3)=-cos(pi/3)=-1/2#

use your calculator to find cos(2pi/7) and sin(3pi/14). they should be equal to each other. make sure your calculator is in radians mode, or get the equation in equivalent degree mode and use your calculator in degree mode.

Jul 24, 2016 · #rArrarccos(cos(2pi))=2pi# Answer link. Related questions. What are the Basic Inverse Trigonometric ...

Apr 7, 2016 · Zero Apply the trig identity: cos (a - b) = cos a.cos b + sin a.sin b cos ((2pi)/3 - pi/6) = cos ((2pi)/3).cos (pi/6) + sin ((2pi)/3).sin (pi/6) Trig table gives ...

Jan 15, 2016 · We know the cosine subtraction formula: #cos(alpha-beta)=cosalphacosbeta+sinalphasinbeta# Thus, #cos((2pi)/3-a)=cos((2pi)/3)cos(a)+sin((2pi)/3)sin(a)#

EDIT: Oh, disregard, I just noticed cos in front, you should really write cos(2pi/9) cos(2pi/9) is approx 0.76604444 Plugging this into the equation gives 0 out, therefore cos(2pi/9) is a root.

Dec 14, 2016 · The answer is =-3/4i There are 2 ways for the simplification cos(pi/6)=sqrt3/2 sin(pi/6)=1/2 cos(2pi/3)=-1 ...

Feb 24, 2018 · How do you find the exact value of #cos((2pi)/3)+cos(pi/6)#? Trigonometry Trigonometric Identities and Equations Sum and Difference Identities 1 Answer

Feb 26, 2016 · -pi/6 cos (-2pi/3 ) = sin ( pi/2 + (-2pi/3)) = sin (-pi#/6) arc sin (sin) is unit operator 1.

p = 2pi/(2pi/3) this is the same as p = 2pi * 3 / 2pi the result is that p = 3. if you graph this equation, your x-axis will be in radians and one full cycle of the cosine wave will take up 3 radians. here's the graph of your equation. the normal period is 2pi in radians. the equation of y = cos(x) is really y = cos(1*x). 1 is the frequency.