In which quadrants is cosine positive?

Cosine is a trigonometric function that represents the x-coordinate of a point on the unit circle corresponding to a specific angle. To determine in which quadrants cosine is positive, it's important to understand the characteristics of the unit circle and the coordinate system.

In the coordinate plane, there are four quadrants:

• The first quadrant (0 to 90 degrees) is where both x and y are positive. Therefore, cosine, which is associated with the x-coordinate, is positive.

• The second quadrant (90 to 180 degrees) has a negative x-coordinate and a positive y-coordinate. Here, cosine is negative.

• The third quadrant (180 to 270 degrees) has both a negative x and y-coordinate, which means cosine is also negative in this region.

• The fourth quadrant (270 to 360 degrees) has a positive x-coordinate and a negative y-coordinate. Thus, cosine is positive in this quadrant.

Based on this analysis, cosine is positive in the first and fourth quadrants, making the correct answer the combination of these quadrants.