The Purplemath Forums

Hello! I'm new to the board and am stuck on these types of questions: Referring to a graph of y = sin x or y = cos x find the exact values of x in the interval [0, 4pi] that satisfy the equation: sin x = 1/2 I know that I am looking for the values of x where the graph of sin x intersects graph of th...

Hmmm. I'm not sure what you mean. The answers are pi/6, 5pi/6, 13pi/6, 17pi/6.

Part of the problem is that since I've never had a trig class, I don't know what I am suppose to memorize and what I am suppose to be able to derive, which is only important since tests are timed, but I've made a point to memorize the reference angles and make sure I can derive them. But anyway, aft...

You're exactly right about the height. You look at the graph and, knowing that sin(x) = 1/2 for x = pi/6 (or for x = 30 degrees; take your pick), you look for the places where the graph looks to be about right for the height. Then you add or subtract 30 degrees (or pi/6) from the closest known angl...

This question is in the exercises associated with reference angles. I understand the reference angle part, but there is a question, which I don't know how to work with or without a calculator. Approximate to three decimal places: a) sin 73deg 20' b) cos 0.68 The answers are a) .958 and b) .778 thoug...