Find the coordinates of the point (a, b). a=?

(cos π/4, sin π/4) or approx. (0.707, 0.707)

Step-by-step explanation:

The length of the blue ray is 1.  That's the same for any ray drawn inside the circle.

Then a = cos π/4 and b = sin π/4.

The cartesian coordinates of the point (a, b) are

(cos π/4, sin π/4) or approx. (0.707, 0.707)

answer: the common difference is -0.10

you didn't give me the choices, so i will just give you the graph so you can look at your choices and choose the right one.