Evaluate. Write your answers in simplified, rationalized forms. Do not round.
sin 30° =
COS 30°=
tan 30° =
The correct answer and explanation is:
The values for sin 30°, cos 30°, and tan 30° are commonly known, and they are derived from the properties of a 30°-60°-90° triangle, which has specific ratios for its sides.
sin 30°:
For a 30° angle in a right triangle, the opposite side is half the length of the hypotenuse. The ratio of the opposite side to the hypotenuse is defined as sine. In a 30°-60°-90° triangle, the sides have a ratio of 1:√3:2. Therefore, the sine of 30° is: sin30°=12\sin 30° = \frac{1}{2}
cos 30°:
The cosine of an angle in a right triangle is the ratio of the adjacent side to the hypotenuse. For a 30°-60°-90° triangle, the adjacent side for 30° is √3, and the hypotenuse is 2. So: cos30°=32\cos 30° = \frac{\sqrt{3}}{2}
tan 30°:
The tangent of an angle is the ratio of the opposite side to the adjacent side. In a 30°-60°-90° triangle, for the 30° angle, the opposite side is 1, and the adjacent side is √3. Therefore: tan30°=13\tan 30° = \frac{1}{\sqrt{3}}
To rationalize the denominator: tan30°=13×33=33\tan 30° = \frac{1}{\sqrt{3}} \times \frac{\sqrt{3}}{\sqrt{3}} = \frac{\sqrt{3}}{3}
Summary of answers:
- sin30°=12\sin 30° = \frac{1}{2}
- cos30°=32\cos 30° = \frac{\sqrt{3}}{2}
- tan30°=33\tan 30° = \frac{\sqrt{3}}{3}
These values are derived from the special properties of a 30°-60°-90° triangle, where the ratios of the sides are consistent and can be used to determine trigonometric values for these angles.