What is the sign of cosine in Quadrant 1?

In the context of the unit circle and the coordinate plane, the cosine function corresponds to the x-coordinate of a point on the unit circle. In the first quadrant, both the x-coordinate (cosine) and the y-coordinate (sine) are positive because all the angles in this quadrant range from 0 to 90 degrees (or 0 to π/2 radians).

Thus, cosine is positive in this quadrant, which aligns with the fact that the range of angles results in both coordinates being above the x-axis and to the right of the y-axis. As a result, when considering the value of cosine for any angle measured in the first quadrant, you can confidently affirm that it will yield a positive result. Therefore, the correct answer reflects this vital relationship between angle measures and the signs of the trigonometric functions.