Solve sinxcossinxcospi/6+cosxsinxπ6+cosxsinxpi/6=1/sqrt2π6=12 for 0<=x,=2pi0x,=2π ?

1 Answer
May 30, 2017

pi/12; (7pi)/12π12;7π12

Explanation:

Develop the left side
LS = sin x.cos (pi/6) + cos x.sin (pi/6) = sin (x + pi/6)LS=sinx.cos(π6)+cosx.sin(π6)=sin(x+π6)
Equation to solve:
sin (x + pi/6) = 1/sqrt2sin(x+π6)=12
Trig table and unit circle give 2 solutions:
a. x + pi/6 = pi/4x+π6=π4
x = pi/4 - pi/6 = pi/12π4π6=π12
b. x + pi/6 = pi - pi/4 = (3pi)/4x+π6=ππ4=3π4
x = x=(3pi)/4 - pi/6 = (7pi)/12#