/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 35 Rewrite each angle in radian mea... [FREE SOLUTION] | 91Ó°ÊÓ

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Rewrite each angle in radian measure as a multiple of \(\pi\). (Do not use a calculator.) (a) \(120^{\circ}\) (b) \(-20^{\circ}\)

Short Answer

Expert verified
The measure in radians for \(120^{\circ}\) is \(2\pi/3\). The measure in radians for \(-20^{\circ}\) is \(-\pi/9\).

Step by step solution

01

Conversion Formula

The first step is remembering the conversion formula, which states that \(180^{\circ}\) is equal to \(\pi\) radians. This means that to turn degrees into radians, we multiply by \(\pi/180^{\circ}\).
02

Convert \(120^{\circ}\) to Radians

To convert \(120^{\circ}\) into radians, one must multiply by the conversion factor \(\pi/180^{\circ}\) as follows: \(120^{\circ} \times (\pi/180^{\circ}) = 2\pi/3\). So, \(120^{\circ}\) is equivalent to \(2\pi/3\) radians.
03

Convert \(-20^{\circ}\) to Radians

To turn \(-20^{\circ}\) into radians, we essentially do the same thing. That is, \(-20^{\circ}\) is multiplied by the conversion factor \(\pi/180^{\circ}\): \(-20^{\circ} \times (\pi/180^{\circ}) = -\pi/9\). So, \(-20^{\circ}\) is equivalent to \(-\pi/9\) radians.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Radian Measure
The term 'radian measure' refers to a standard unit of angular measurement used in many areas of mathematics, especially trigonometry. Unlike degrees, which divide a circle into 360 equal parts, radian measure divides a circle based on its radius. One radian is the angle made at the center of a circle by an arc whose length is equal to the radius of the circle.

Since the circumference of a circle is \(2\pi r\), where \(r\) is the radius, a circle has \(2\pi\) radians in total. This relationship suggests that 360 degrees, encompassing a full circle, is equivalent to \(2\pi\) radians. Consequently, \(1^\circ\) is equal to approximately \(\pi/180\) radians.
Degree to Radian Conversion
Converting from degrees to radians is an essential skill in trigonometry. The process involves using a simple conversion factor-based on the relationship between degrees and radians. Since we know that \(360^\circ = 2\pi\) radians, we can deduce the conversion formula: \(1^\circ = \pi/180\) radians.

To convert an angle from degrees to radians, multiply the angle in degrees by \(\pi/180\). For instance, to convert \(90^\circ\) to radians, compute \(90^\circ \times (\pi/180^\circ) = \pi/2\). This basic formula is the cornerstone of converting angles between these two commonly used units of measure.
Trigonometry
Trigonometry is a branch of mathematics that studies relationships involving lengths and angles of triangles. The name 'trigonometry' comes from the Greek words 'trigonon', meaning 'triangle', and 'metron', meaning 'measure'. It primarily deals with sine, cosine, and tangent functions, which are ratios of sides in a right-angled triangle. These functions are foundational to various applications, such as physics, engineering, and even music theory.

Understanding how to convert degrees to radians plays a critical role in trigonometry since trigonometric functions in calculus are often calculated in radians. The radian measure allows for the direct application of these functions in formulas and series expansions.
Angle Measurement
Angle measurement is vital in many fields, including mathematics, engineering, surveying, navigation, and astronomy. There are two primary systems for measuring angles: degrees and radians. A degree is a non-SI unit of angular measure, whereas a radian is the SI unit for measuring angles, based on the radius of a circle.

Degrees are often used in navigation and geography, as the Earth is divided into longitudes and latitudes that are measured in degrees. However, radians are more suitable in mathematical analysis and physics due to their natural link to the properties of a circle. As such, being fluent in converting between these systems enables more versatile problem-solving across disciplines.

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Most popular questions from this chapter

A Ferris wheel is built such that the height \(h\) (in feet) above ground of a seat on the wheel at time \(t\) (in seconds) can be modeled by $$h(t)=53+50 \sin \left(\frac{\pi}{10} t-\frac{\pi}{2}\right)$$ (a) Find the period of the model. What does the period tell you about the ride? (b) Find the amplitude of the model. What does the amplitude tell you about the ride? (c) Use a graphing utility to graph one cycle of the model.

Sketch a graph of the function. $$h(v)=\arccos \frac{v}{2}$$

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Sketch the graph of \(y=\cos b x\) for \(b=\frac{1}{2}\) \(2,\) and \(3 .\) How does the value of \(b\) affect the graph? How many complete cycles of the graph of \(y\) occur between 0 and \(2 \pi\) for each value of \(b ?\)

The current \(I\) (in amperes) when 100 volts is applied to a circuit is given by $$I=5 e^{-2 t} \sin t$$ where \(t\) is the time (in seconds) after the voltage is applied. Approximate the current at \(t=0.7\) second after the voltage is applied.

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