Phase angle

Phase angle 15.18 degrees. What is this value in radians?

length of a arc

Two people 1.8m tall walk from each other until they can no longer see each other (due to the curvature of the earth which has a radius of 6378km). Assuming nothing else blocks their view, how far do they have to walk? Note. I cant get my head around how this relates to what we've learned about radius and arc length.

Using triangle ABC, show that the form (cos(A/2))^x is able to find side lengths.

Let ABC be a triangle. Prove that (cos(A/2))^x, (cos(B/2))^x, and (cos(C/2))^x are the lengths of a triangle for any x greater than or equal to 0. From what I have found in my books, it is impossible to solve for side lengths of a triangle using AAA b/c there is no formula to do so. It is possible to find similar triangles, though. From talking to the professor, he said that the side lengths are for another triangle. When I run "sample problems" the lengths that I get are less than or equal to 1. I understand by closure that the (A/2) is just an ordinary angle and that they are all positive numbers. I also believe that one of the original angles would have to be 90 degrees. I have... click for more

Prove or disprove identity

3sin(Theta)-4cos(Theta)=5sin(Theta + cos^-1[3/5])

Prove or disprove an identity

sec^2(X)csc^2(X)=sec^2(X)+csc^2(X)