In Exercises circvaluefirst - circvaluelast, find the exact value or state that it is undefined.
\(\tan \left ( \frac {\pi }{4} \right )\)

\(\tan \left ( \frac {\pi }{4} \right ) = 1\)
\(\sec \left ( \frac {\pi }{6} \right )\)

\(\sec \left ( \frac {\pi }{6} \right ) = \frac {2\sqrt {3}}{3}\)
\(\csc \left ( \frac {5\pi }{6} \right )\)

\(\csc \left ( \frac {5\pi }{6} \right ) = \answer {2}\)

\(\cot \left ( \frac {4\pi }{3} \right )\)

\(\cot \left ( \frac {4\pi }{3} \right ) = \frac {\sqrt {3}}{3}\)
\(\tan \left ( -\frac {11\pi }{6} \right )\)

\(\tan \left ( -\frac {11\pi }{6} \right ) = \answer {\frac {\sqrt {3}}{3}}\)

\(\sec \left ( -\frac {3\pi }{2} \right )\)

\(\sec \left ( -\frac {3\pi }{2} \right )\) is undefined

\(\csc \left ( -\frac {\pi }{3} \right )\)

\(\csc \left ( -\frac {\pi }{3} \right ) = -\frac {2\sqrt {3}}{3}\)

\(\cot \left ( \frac {13\pi }{2} \right )\)

\(\cot \left ( \frac {13\pi }{2} \right ) = \answer {0}\)

\(\tan \left ( 117\pi \right )\)

\(\tan \left ( 117\pi \right ) = 0\)
\(\sec \left ( -\frac {5\pi }{3} \right )\)

\(\sec \left ( -\frac {5\pi }{3} \right ) = \answer {2}\)

\(\csc \left ( 3\pi \right )\)

\(\csc \left ( 3\pi \right )\) is undefined
\(\cot \left ( -5\pi \right )\)

\(\cot \left ( -5\pi \right )\) is undefined
\(\tan \left ( \frac {31\pi }{2} \right )\)

\(\tan \left ( \frac {31\pi }{2} \right )\) is undefined
\(\sec \left ( \frac {\pi }{4} \right )\)

\(\sec \left ( \frac {\pi }{4} \right ) = \answer {\sqrt {2}}\)

\(\csc \left ( -\frac {7\pi }{4} \right )\)

\(\csc \left ( -\frac {7\pi }{4} \right ) = \sqrt {2}\)
\(\cot \left ( \frac {7\pi }{6} \right )\)

\(\cot \left ( \frac {7\pi }{6} \right ) = \answer {\sqrt {3}}\)

\(\tan \left ( \frac {2\pi }{3} \right )\)

\(\tan \left ( \frac {2\pi }{3} \right ) = -\sqrt {3}\)
\(\sec \left ( -7\pi \right )\)

\(\sec \left ( -7\pi \right ) = \answer {-1}\)

\(\csc \left ( \frac {\pi }{2} \right )\)

\(\csc \left ( \frac {\pi }{2} \right ) = 1\)
\(\cot \left ( \frac {3\pi }{4} \right )\)

\(\cot \left ( \frac {3\pi }{4} \right ) = \answer {-1}\)

In Exercises whereisanglefirst - whereisanglelast, use the given the information to determine the quadrant in which the terminal side of the angle lies when plotted in standard position.
\(\sin (\theta ) > 0\) but \(\tan (\theta ) < 0\).

\(\theta \) is in Quadrant II.

\(\cot (\alpha ) > 0\) but \(\cos (\alpha ) < 0\).

\(\alpha \) is in Quadrant \(\answer {III}\)

\(\sin (\beta ) > 0\) and \(\tan (\beta ) > 0\).

\(\beta \) is in Quadrant I.
\(\cos (\gamma ) > 0\) but \(\cot (\gamma ) < 0\).

\(\gamma \) is in Quadrant \(\answer {IV}\).

In Exercises findothercircfirst - findothercirclast, use the given the information to find the exact values of the circular functions of \(\theta \).
\(\sin (\theta ) = \frac {3}{5}\) with \(\theta \) in Quadrant II

\(\sin (\theta ) = \frac {3}{5}\)

\(\cos (\theta ) = -\frac {4}{5}\)

\(\tan (\theta ) = -\frac {3}{4}\)

\(\csc (\theta ) = \frac {5}{3}\)

\(\sec (\theta ) = -\frac {5}{4}\)

\(\cot (\theta ) = -\frac {4}{3}\)

\(\tan (\theta ) = \frac {12}{5}\) with \(\theta \) in Quadrant III

\(\sin (\theta ) = \answer {-\frac {12}{13}}\)

\(\cos (\theta ) = \answer {-\frac {5}{13}}\)

\(\tan (\theta ) = \answer {\frac {12}{5}}\)

\(\csc (\theta ) = \answer {-\frac {13}{12}}\)

\(\sec (\theta ) = \answer {-\frac {13}{5}}\)

\(\cot (\theta ) = \answer {\frac {5}{12}}\)

\(\csc (\theta ) = \frac {25}{24}\) with \(\theta \) in Quadrant I

\(\sin (\theta ) = \frac {24}{25}\)

\(\cos (\theta ) = \frac {7}{25}\)

\(\tan (\theta ) = \frac {24}{7}\)

\(\csc (\theta ) = \frac {25}{24}\)

\(\sec (\theta ) = \frac {25}{7}\)

\(\cot (\theta ) = \frac {7}{24}\)

\(\sec (\theta ) = 7\) with \(\theta \) in Quadrant IV

\(\sin (\theta ) = \answer {\frac {-4\sqrt {3}}{7}}\)

\(\cos (\theta ) = \answer {\frac {1}{7}}\)

\(\tan (\theta ) = \answer {-4\sqrt {3}}\)

\(\csc (\theta ) = \answer {-\frac {7\sqrt {3}}{12}}\)

\(\sec (\theta ) = \answer {7}\)

\(\cot (\theta ) = \answer {-\frac {\sqrt {3}}{12}}\)

\(\csc (\theta ) = -\frac {10\sqrt {91}}{91}\) with \(\theta \) in Quadrant III

\(\sin (\theta ) = -\frac {\sqrt {91}}{10}\)

\(\cos (\theta ) = -\frac {3}{10}\)

\(\tan (\theta ) = \frac {\sqrt {91}}{3}\)

\(\csc (\theta ) = -\frac {10\sqrt {91}}{91}\)

\(\sec (\theta ) = -\frac {10}{3}\)

\(\cot (\theta ) = \frac {3\sqrt {91}}{91}\)

\(\cot (\theta ) = -23\) with \(\theta \) in Quadrant II

\(\sin (\theta ) = \answer {\frac {\sqrt {530}}{530}}\)

\(\cos (\theta ) = \answer {-\frac {23\sqrt {530}}{530}}\)

\(\tan (\theta ) = \answer {-\frac {1}{23}}\)

\(\csc (\theta ) = \answer {\sqrt {530}}\)

\(\sec (\theta ) = \answer {-\frac {\sqrt {530}}{23}}\)

\(\cot (\theta ) = \answer {-23}\)

\(\tan (\theta ) = -2\) with \(\theta \) in Quadrant IV.

\(\sin (\theta ) = -\frac {2\sqrt {5}}{5}\)

\(\cos (\theta ) = \frac {\sqrt {5}}{5}\)

\(\tan (\theta ) = -2\)

\(\csc (\theta ) = -\frac {\sqrt {5}}{2}\)

\(\sec (\theta ) = \sqrt {5}\)

\(\cot (\theta ) = -\frac {1}{2}\)

\(\sec (\theta ) = -4\) with \(\theta \) in Quadrant II.

\(\sin (\theta ) = \answer {\frac {\sqrt {15}}{4}}\)

\(\cos (\theta ) = \answer {-\frac {1}{4}}\)

\(\tan (\theta ) = \answer {-\sqrt {15}}\)

\(\csc (\theta ) = \answer {\frac {4\sqrt {15}}{15}}\)

\(\sec (\theta ) = \answer {-4}\)

\(\cot (\theta ) = \answer {-\frac {\sqrt {15}}{15}}\)

\(\cot (\theta ) = \sqrt {5}\) with \(\theta \) in Quadrant III.

\(\sin (\theta ) = -\frac {\sqrt {6}}{6}\)

\(\cos (\theta ) = -\frac {\sqrt {30}}{6}\)

\(\tan (\theta ) = \frac {\sqrt {5}}{5}\)

\(\csc (\theta ) = -\sqrt {6}\)

\(\sec (\theta ) = -\frac {\sqrt {30}}{5}\)

\(\cot (\theta ) = \sqrt {5}\)

\(\cos (\theta ) = \frac {1}{3}\) with \(\theta \) in Quadrant I.

\(\sin (\theta ) = \answer {\frac {2\sqrt {2}}{3}}\)

\(\cos (\theta ) = \answer {\frac {1}{3}}\)

\(\tan (\theta ) = \answer {2\sqrt {2}}\)

\(\csc (\theta ) = \answer {\frac {3\sqrt {2}}{4}}\)

\(\sec (\theta ) = \answer {3}\)

\(\cot (\theta ) = \answer {\frac {\sqrt {2}}{4}}\)

\(\cot (\theta ) = 2\) with \(0 < \theta < \frac {\pi }{2}\).

\(\sin (\theta ) = \frac {\sqrt {5}}{5}\)

\(\cos (\theta ) = \frac {2\sqrt {5}}{5}\)

\(\tan (\theta ) = \frac {1}{2}\)

\(\csc (\theta ) = \sqrt {5}\)

\(\sec (\theta ) = \frac {\sqrt {5}}{2}\)

\(\cot (\theta ) = 2\)

\(\csc (\theta ) = 5\) with \(\frac {\pi }{2} < \theta < \pi \).

\(\sin (\theta ) = \answer {\frac {1}{5}}\)

\(\cos (\theta ) = \answer {-\frac {2\sqrt {6}}{5}}\)

\(\tan (\theta ) = \answer {-\frac {\sqrt {6}}{12}}\)

\(\csc (\theta ) = \answer {5}\)

\(\sec (\theta ) = \answer {-\frac {5\sqrt {6}}{12}}\)

\(\cot (\theta ) = \answer {-2\sqrt {6}}\)

\(\tan (\theta ) = \sqrt {10}\) with \(\pi < \theta < \frac {3\pi }{2}\).

\(\sin (\theta ) = -\frac {\sqrt {110}}{11}\)

\(\cos (\theta ) = -\frac {\sqrt {11}}{11}\)

\(\tan (\theta ) = \sqrt {10}\)

\(\csc (\theta ) = -\frac {\sqrt {110}}{10}\)

\(\sec (\theta ) = -\sqrt {11}\)

\(\cot (\theta ) = \frac {\sqrt {10}}{10}\)

\(\sec (\theta ) = 2\sqrt {5}\) with \(\frac {3\pi }{2} < \theta < 2\pi \).

\(\sin (\theta ) = \answer {-\frac {\sqrt {95}}{10}}\)

\(\cos (\theta ) = \answer {\frac {\sqrt {5}}{10}}\)

\(\tan (\theta ) = \answer {-\sqrt {19}}\)

\(\csc (\theta ) = \answer {-\frac {2\sqrt {95}}{19}}\)

\(\sec (\theta ) = \answer {2\sqrt {5}}\)

\(\cot (\theta ) = \answer {-\frac {\sqrt {19}}{19}}\)

In Exercises circcalcfirst - circcalclast, use your calculator to approximate the given value to three decimal places. Make sure your calculator is in the proper angle measurement mode!
\(\csc (78.95^{\circ })\)

\(\csc (78.95^{\circ }) \approx 1.019\)
\(\tan (-2.01)\)

\(\tan (-2.01) \approx \answer {2.129}\)

\(\cot (392.994)\)

\(\cot (392.994) \approx 3.292\)
\(\sec (207^{\circ })\)

\(\sec (207^{\circ }) \approx \answer {-1.122}\)

\(\csc (5.902)\)

\(\csc (5.902) \approx -2.688\)
\(\tan (39.672^{\circ })\)

\(\tan (39.672^{\circ }) \approx \answer {0.829}\)

\(\cot (3^{\circ })\)

\(\cot (3^{\circ }) \approx 19.081\)
\(\sec (0.45)\)

\(\sec (0.45) \approx \answer {1.111}\)

In Exercises circequanglefirst - circequanglelast, find all of the angles which satisfy the equation.

For the problems where you are prompted to type in an answer, type a response in the range \(0 \leq \theta < 2\pi \).

\(\tan (\theta ) = \sqrt {3}\)

\(\theta = \frac {\pi }{3} + \pi k\) for any integer \(k\)
\(\sec (\theta ) = 2\)

\(\theta = \answer {\frac {\pi }{3}} + 2\pi k\) (Quadrant I) or \(\theta = \answer {\frac {5\pi }{3}} + 2\pi k\) (Quadrant III) for any integer \(k\)

\(\csc (\theta ) = -1\)

\(\theta = \frac {3\pi }{2} + 2\pi k\) for any integer \(k\).
\(\cot (\theta ) = \frac {\sqrt {3}}{3}\)

\(\theta = \answer {\frac {\pi }{3}} + \pi k\) (Quadrant I) for any integer \(k\)

\(\tan (\theta ) = 0\)

\(\theta = \pi k\) for any integer \(k\)
\(\sec (\theta ) = 1\)

\(\theta = 2\pi k\) for any integer \(k\)
\(\csc (\theta ) = 2\)

\(\theta = \answer {\frac {\pi }{6}} + 2\pi k\) (Quadrant I) or \(\theta = \answer {\frac {5\pi }{6}} + 2\pi k\) (Quadrant II) for any integer \(k\).

\(\cot (\theta ) = 0\)

\(\theta = \frac {\pi }{2} + \pi k\) for any integer \(k\)
\(\tan (\theta ) = -1\)

\(\theta = \answer {\frac {3\pi }{4}} + \pi k\) (Quadrant II) for any integer \(k\)

\(\sec (\theta ) = 0\)

\(\sec (\theta ) = 0\) has no solution.

\(\csc (\theta ) = -\frac {1}{2}\)

\(\csc (\theta ) = -\frac {1}{2}\) has no (real) solution.

\(\sec (\theta ) = -1\)

\(\theta = \pi + 2\pi k = (2k+1)\pi \) for any integer \(k\)
\(\tan (\theta ) = -\sqrt {3}\)

\(\theta = \answer {\frac {2\pi }{3}} + \pi k\) (Quadrant II) for any integer \(k\)

\(\csc (\theta ) = -2\)

\(\theta = \frac {7\pi }{6} + 2\pi k\) or \(\theta = \frac {11\pi }{6} + 2\pi k\) for any integer \(k\)
\(\cot (\theta ) = -1\)

\(\theta = \answer {\frac {3\pi }{4}} + \pi k\) (Quadrant II) for any integer \(k\)

In Exercises circequtfirst - circequtlast, solve the equation for \(t\). Give exact values.
\(\cot (t) = 1\)

\(t = \frac {\pi }{4} + \pi k\) for any integer \(k\)
\(\tan (t) = \frac {\sqrt {3}}{3}\)

\(t = \frac {\pi }{6} + \pi k\) for any integer \(k\)
\(\sec (t) = -\frac {2\sqrt {3}}{3}\)

\(t = \frac {5\pi }{6} + 2\pi k\) or \(t = \frac {7\pi }{6} + 2\pi k\) for any integer \(k\)
\(\csc (t) = 0\)

\(\csc (t) = 0\) has no solution.
\(\cot (t) = -\sqrt {3}\)

\(t = \frac {5\pi }{6} + \pi k\) for any integer \(k\)
\(\tan (t) = -\frac {\sqrt {3}}{3}\)

\(t = \frac {5\pi }{6} + \pi k\) for any integer \(k\)
\(\sec (t) = \frac {2\sqrt {3}}{3}\)

\(t = \frac {\pi }{6} + 2\pi k\) or \(t = \frac {11\pi }{6} + 2\pi k\) for any integer \(k\)
\(\csc (t) = \frac {2\sqrt {3}}{3}\)

\(t = \frac {\pi }{3} + 2\pi k\) or \(t = \frac {2\pi }{3} + 2\pi k\) for any integer \(k\)
In Exercises decomposebasicothercircularfirst - decomposebasicothercircularlast, write the given function as a nontrivial decomposition of functions as directed.
For \(f(t) = 3t^2 + 2 \tan (3t)\), find functions \(g\) and \(h\) so that \(f=g+h\).

One solution is \(g(t) = 3t^2\) and \(h(t) = 2\tan (3t)\).
For \(f(\theta ) = \sec (\theta ) - \tan (\theta )\), find functions \(g\) and \(h\) so that \(f=g-h\).

One solution is \(g(\theta ) = \sec (\theta )\) and \(h(\theta ) = \tan (\theta )\).
For \(f(t) = -\csc (t) \cot (t)\), find functions \(g\) and \(h\) so that \(f=gh\).

One solution is \(g(t) = -\csc (t)\) and \(h(t) = \cot (t)\).
For \(r(t) = \frac {\tan (3t)}{t}\), find functions \(f\) and \(g\) so \(r = \frac {f}{g}\).

One solution is \(f(t) = \tan (3t)\) and \(g(t) = t\).
For \(T(\theta ) =\tan (4 \theta )\), find functions \(f\) and \(g\) so \(T = g \circ f\).

One solution is \(f(\theta ) = 4 \theta \) and \(g(\theta ) = \tan (\theta )\).
For \(s(\theta ) = \sec ^{2}(\theta )\), find functions \(f\) and \(g\) so \(s = g \circ f\).

Since \(\sec ^{2}(\theta ) = (\sec (\theta ))^2\), one solution is \(f(\theta ) = \sec (\theta )\) and \(g(\theta ) = \theta ^2\).
For \(L(x) = \ln (\sin (x) )\), find functions \(f\) and \(g\) so \(L = g \circ f\).

One solution is \(f(x) = \sin (x)\) and \(g(x) = \ln (x)\).
For \(\ell (\theta ) = \ln | \sec (\theta ) - \tan (\theta )|\), find find functions \(f\), \(g\), and \(h\) so \(\ell = h \circ (f-g)\).

One solution is \(f(\theta ) = \sec (\theta )\), \(g(\theta ) = \tan (\theta )\), and \(h(\theta ) = \ln | \theta |\).
Let \(S(t) = \sin (t)\) and \(C(t) = \cos (t)\), \(F(t) = \tan (t)\), and \(G(t) = \cot (t)\). Explain why \(F = \frac {S}{C}\) but \(F \neq \frac {1}{G}\).

HINT: Think about domains …

For each function \(T(t)\) listed below, compute the average rate of change over the indicated interval. What trends do you notice? Compare your answer with what you discovered in Section TheCircularFunctionsSineandCosine number sinearcexercise. Be sure your calculator is in radian mode!
\[ \begin{array}{|r||c|c|c|} \hline T(t) & [-0.1, 0.1] & [-0.01, 0.01] &[-0.001, 0.001] \\ \hline \tan (t) &&& \\ \hline \tan (2t) &&& \\ \hline \tan (3t) &&& \\ \hline \tan (4t) &&& \\ \hline \end{array} \]

As we zoom in towards \(0\), the average rate of change of \(\tan (k t)\) approaches \(k\). This is the same trend we observed for \(\sin (k t)\) in Section TheCircularFunctionsSineandCosine number sinearcexercise.

\[ \begin{array}{|r||c|c|c|} \hline T(t) & [-0.1, 0.1] & [-0.01, 0.01] &[-0.001, 0.001] \\ \hline \tan (t) & \approx 1.0033 & \approx 1 & \approx 1 \\ \hline \tan (2t) & \approx 2.0271 & \approx 2.0003 & \approx 2 \\ \hline \tan (3t) & \approx 3.0933 & \approx 3.0009 & \approx 3 \\ \hline \tan (4t) & \approx 4.2279 & \approx 4.0021 & \approx 4 \\ \hline \end{array} \]
We wish to establish the inequality \(\cos (\theta ) < \frac {\sin (\theta )}{\theta } < 1\) for \(0 < \theta < \frac {\pi }{2}.\) Use the diagram from the beginning of the section, partially reproduced below, to answer the following.
  1. Show that triangle \(OPB\) has area \(\frac {1}{2} \sin (\theta )\) and triangle \(OQB\) has area \(\frac {1}{2} \tan (\theta )\).
  2. Show that the circular sector \(OPB\) with central angle \(\theta \) has area \(\frac {1}{2} \theta \).
  3. Comparing areas, show that \(\sin (\theta ) < \theta < \tan (\theta )\) for \(0 < \theta < \frac {\pi }{2}.\)
  4. Use the inequality \(\sin (\theta ) < \theta \) to show that \(\frac {\sin (\theta )}{\theta } < 1\) for \(0 < \theta < \frac {\pi }{2}.\)
  5. Use the inequality \(\theta < \tan (\theta )\) to show that \(\cos (\theta ) < \frac {\sin (\theta )}{\theta }\) for \(0 < \theta < \frac {\pi }{2}.\) Combine this with the previous part to complete the proof.
Show that \(\cos (\theta ) < \frac {\sin (\theta )}{\theta } < 1\) also holds for \(-\frac {\pi }{2}< \theta < 0\).
Use the results from Exercises sintovertexercise1 and sintovertexercise2 along with the Squeeze Theorem, to prove \(\ds { \lim _{\theta \rightarrow 0}}\) \( \frac {\sin (\theta )}{\theta } = 1\).