1. Suppose that $0 < t < \frac{\pi}{2}$, and that $\displaystyle \csc t=2$ . Find the values of the trigonometric functions $\sin(t)$, $\cos(t)$, and $\tan(t)$.

    $\displaystyle \left[ \sin t=-{{1}\over{3}} , \cos t={{1}\over{2}} , \tan t=-{{2
}\over{3}} \right] $

    $\displaystyle \left[ \sin t={{1}\over{2}} , \cos t={{\sqrt{3}}\over{2}} , \tan t=
{{1}\over{\sqrt{3}}} \right] $

    $\displaystyle \left[ \sin t={{\sqrt{3}}\over{2}} , \cos t={{1}\over{2}} , \tan t=
\sqrt{3} \right] $

    $\displaystyle \left[ \sin t={{1}\over{2}} , \cos t=-{{1}\over{3}} , \tan t=-{{3
}\over{2}} \right] $

  2. Choose the correct trigonometric identity.

    $\sin( t+{{\pi}\over{2}}) =
-\sin t$

    $\sin( t+{{\pi}\over{2}}) =
\cos t$

    $\sin( t+{{\pi}\over{2}}) =
\sin t$

    $\sin( t+{{\pi}\over{2}}) =
-\cos t$

  3. Choose the correct trigonometric identity.

    $\displaystyle \left(1-\sin ^2t\right)\,\left(\tan ^2t+1\right)=-{{2\,\sin ^4t+
\sin ^2t-1}\over{\cos ^2t}}$

    $\displaystyle \left(1-\sin ^2t\right)\,\left(\tan ^2t+1\right)=1$

    $\displaystyle \left(1-\sin ^2t\right)\,\left(\tan ^2t+1\right)=2\,\cos ^2t-1$

    $\displaystyle \left(1-\sin ^2t\right)\,\left(\tan ^2t+1\right)={{\sin ^2t+1
}\over{\cos ^2t}}$

  4. Choose the correct trigonometric identity.

    $\displaystyle \sin x-\cos x\,\cot x=-\csc x$

    $\displaystyle \sin x-\cos x\,\cot x=\csc x$

    $\displaystyle \sin x-\cos x\,\cot x=2\,\sin x-\csc x$

    $\displaystyle \sin x-\cos x\,\cot x={{2\,\csc x}\over{\left(\sec x\right)^2}}-
\csc x$

  5. Choose the correct trigonometric identity.

    $\displaystyle \sin x\,\tan x+\cos x={{2\,\sec x}\over{\left(\csc x\right)^2}}-
\sec x$

    $\displaystyle \sin x\,\tan x+\cos x=\sec x$

    $\displaystyle \sin x\,\tan x+\cos x=-\sec x$

    $\displaystyle \sin x\,\tan x+\cos x=2\,\cos x-\sec x$

  6. Find the derivative $f'(x)$ for $f(x) =\displaystyle {{\tan x}\over{x^2}} $ .

    $f'(x) =\displaystyle {{x\,\left(\csc x\right)^2+2\,\cot x}\over{x^3}} $ $f'(x) =\displaystyle {{2\,\tan x-x\,\left(\sec x\right)^2}\over{x^3}} $ $f'(x) =\displaystyle -{{x\,\left(\csc x\right)^2+2\,\cot x}\over{x^3}} $ $f'(x) =\displaystyle -{{2\,\tan x-x\,\left(\sec x\right)^2}\over{x^3}} $

  7. Suppose that $\frac{\pi}{2} < t < \pi$, and that $\displaystyle \csc t=5$ . Find the values of the trigonometric functions $\sin(t)$, $\cos(t)$, and $\tan(t)$.

    $\displaystyle \left[ \sin t={{1}\over{5}} , \cos t=-{{2\,\sqrt{6}}\over{5}} ,
\tan t=-{{1}\over{2\,\sqrt{6}}} \right] $

    $\displaystyle \left[ \sin t={{1}\over{5}} , \cos t={{2\,\sqrt{6}}\over{5}} ,
\tan t={{1}\over{2\,\sqrt{6}}} \right] $

    $\displaystyle \left[ \sin t=-{{2\,\sqrt{6}}\over{5}} , \cos t={{1}\over{5}} ,
\tan t=-2\,\sqrt{6} \right] $

    $\displaystyle \left[ \sin t={{2\,\sqrt{6}}\over{5}} , \cos t={{1}\over{5}} ,
\tan t=2\,\sqrt{6} \right] $

  8. Suppose that $\displaystyle g\left( {{2\,\pi}\over{3}} \right) = -3 $ and $\displaystyle g'\left( {{2\,\pi}\over{3}} \right) = -2 $. Then find the derivative $\displaystyle f'\left( {{2\,\pi}\over{3}} \right)$ for $f(x) = \displaystyle g\left(x\right)\,\cot x $ .

    $\displaystyle \sqrt{3}$ $\displaystyle {{2}\over{\sqrt{3}}}-4$ $\displaystyle {{2}\over{\sqrt{3}}}+4$ −2 $\displaystyle 4-{{2}\over{\sqrt{3}}}$

  9. Suppose that $\frac{3\pi}{2} < t < 2\pi$, and that $\displaystyle \csc t=-2$ . Find the values of the trigonometric functions $\sin(t)$, $\cos(t)$, and $\tan(t)$.

    $\displaystyle \left[ \sin t=-{{1}\over{2}} , \cos t={{\sqrt{3}}\over{2}} , \tan t=
-{{1}\over{\sqrt{3}}} \right] $

    $\displaystyle \left[ \sin t=-{{1}\over{3}} , \cos t=-{{1}\over{2}} , \tan t={{2
}\over{3}} \right] $

    $\displaystyle \left[ \sin t=-{{1}\over{2}} , \cos t=-{{1}\over{3}} , \tan t={{3
}\over{2}} \right] $

    $\displaystyle \left[ \sin t={{\sqrt{3}}\over{2}} , \cos t=-{{1}\over{2}} , \tan t=
-\sqrt{3} \right] $

  10. Find the derivative $f'(x)$ for $f(x) =\displaystyle e^{x}\,\cot x $ .

    $f'(x) =\displaystyle -e^{x}\,\left(\tan x+\left(\sec x\right)^2\right) $ $f'(x) =\displaystyle e^{x}\,\left(\left(\csc x\right)^2-\cot x\right) $ $f'(x) =\displaystyle -e^{x}\,\left(\left(\csc x\right)^2-\cot x\right) $ $f'(x) =\displaystyle e^{x}\,\left(\tan x+\left(\sec x\right)^2\right) $



Department of Mathematics
Last modified: 2025-06-13