Find all angles θ between 0° and 180° satisfying the given equation. Round your answer to one decimal place. (Enter your answers as a comma-separated list.) cos(θ) = − 3/7

Answer 1

Hello Jon S.,

Which quadrants have negative cosine values such as -3/7? Second and third. Since you are only going from 0^o to 180^o degrees, you have to be in the second quadrant. You can use a calculator to find cos^-1(-3/7) and it should give you the answer. (Make sure it is set for degrees, not radians.)