Question

cos306°+cos234°+cos162°+cos18°=0​

Answer 1

Answer:let me calculate

Step-by-step explanation:

Answer 2

Answer:

Easier than it seems at first. Remember how reference angles work. First, identify what quadrant your angle occupies:

COS 306° -- IV

COS 234° -- III

COS 162° -- II

COS 18° -- I

In each quadrant, you find the reference by heading for the nearest X-axis. In I, it's 0. In 2 & 3, it's 180° and ion IV it is 360° Find a reference angle by finding the angular distance between your angle and the axis. This gets youthe following angles:

306° becomes 360° - 306° = 54°

234° becomes 234° - 180° = 54°

162° becomes 180° - 162° = 18°

18° becomes 18° - 0° = 18°

And finally, remember that trig functions change sign. In quadrants I and IV, COS is positive. In quadrants II and III, negative. So here is what you really had:

Cos 54° - Cos54° - Cos18° + Cos18°

They all cancel out and you get zero.

@Indian Army....