Chapter 1: Problem 35
Sketch each angle in standard position. (a) \(30^{\circ}\) (b) \(150^{\circ}\)
Short Answer
Expert verified
The first angle \(30^{\circ}\) would fall in the first quadrant, between the positive x and y axes. The second angle \(150^{\circ}\) would fall in the second quadrant, between the positive y-axis and the negative x-axis.
Step by step solution
01
Understanding Unit Circle and Angles
The critical point to understand while converting standard position angles to a sketch is that angles are measured from the positive x-axis, and in the counterclockwise direction. The angle increases as we go counterclockwise on the unit circle. The unit circle is a circle with a radius of one that is centered at the origin of the coordinate plane.
02
Sketching the First Angle of \(30^{\circ}\) in standard position
The first angle is \(30^{\circ}\). To sketch this, start from the positive x-axis (which is set at 0 degrees) and measure \(30^{\circ}\) counterclockwise. As we are moving less than a quarter turn, the terminal side of the angle will be in the first quadrant, somewhere between the positive x and y axes.
03
Sketching the Second Angle of \(150^{\circ}\) in standard position
The second angle given is \(150^{\circ}\). Starting again from the positive x-axis, this time we measure half a circle and then subtract \(30^{\circ}\) because \(180-150=30\). So we move around until we are \(30^{\circ}\) short of the negative x-axis. The terminal side of this angle will fall in the second quadrant, between the positive y-axis and the negative x-axis.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Unit Circle
The unit circle is a fundamental concept in trigonometry and helps in understanding angles in standard position. Imagine a circle with a radius of exactly one unit, centered at the origin (0,0) of a coordinate plane. This circle aids in visualizing angles and their trigonometric ratios.
- Every point on the unit circle corresponds to an angle's position.
- The x-coordinates of these points represent cosine values, while y-coordinates represent sine values of the angle.
Degree Measurement
Degree measurement is a way of expressing the size of an angle. A full circle consists of 360 degrees, which makes degrees a familiar unit for measuring angles. This form of measurement is part of the sexagesimal system that divides a circle into 360 equal parts.
- An angle of 90 degrees is a right angle.
- 180 degrees marks a straight line.
- 270 degrees points directly downwards, completing three-quarters of a full circle.
First Quadrant
Quadrants are segments that divide the coordinate plane into four regions. The first quadrant is located in the top-right section of the plane. Here, both x and y coordinates are positive. When an angle in standard position terminates in this quadrant, its measure is between 0 and 90 degrees.
- Angle sizes here range from a straight line (0 degrees) to a vertical line pointing upwards (90 degrees).
- All trigonometric values (sine, cosine, and tangent) are positive in this region.
Second Quadrant
The second quadrant is located in the top-left section of the coordinate plane. In this region, the x-coordinates are negative, but the y-coordinates remain positive. Angles in standard position that terminate here have measures ranging from 90 to 180 degrees.
- Angles in the second quadrant proceed counterclockwise from a vertical line pointing upwards to a horizontal line pointing leftward.
- In this quadrant, sine values remain positive, while cosine and tangent values become negative.