Express cos 7pi/3 as a trigonometric functions of an angle in quadrant 1 (picture provided)

Step-by-step explanation:

To get the angle in the first quadrant, we need to subtract 2π from the angle given as many times we need UNTIL we get an angle that is between 0 degree and 90 degree (1st quadrant).

Let's start by subtracting 2π from the angle given:

This angle is in the 1st quadrant, so we don't need to subtract 2π anymore. Thus we can write:

x=-7

step-by-step explanation:

x+3=-10

-10+3=-7

x=-7