# 7.4 The other trigonometric functions  (Page 5/14)

 Page 5 / 14

## Period of a function

The period     $\text{\hspace{0.17em}}P\text{\hspace{0.17em}}$ of a repeating function $\text{\hspace{0.17em}}f\text{\hspace{0.17em}}$ is the number representing the interval such that $\text{\hspace{0.17em}}f\left(x+P\right)=f\left(x\right)\text{\hspace{0.17em}}$ for any value of $\text{\hspace{0.17em}}x.$

The period of the cosine, sine, secant, and cosecant functions is $\text{\hspace{0.17em}}2\pi .$

The period of the tangent and cotangent functions is $\text{\hspace{0.17em}}\pi .$

## Finding the values of trigonometric functions

Find the values of the six trigonometric functions of angle $\text{\hspace{0.17em}}t\text{\hspace{0.17em}}$ based on [link] .

Find the values of the six trigonometric functions of angle $\text{\hspace{0.17em}}t\text{\hspace{0.17em}}$ based on [link] .

$\begin{array}{l}\mathrm{sin}t=-1,\mathrm{cos}t=0,\mathrm{tan}t=\text{Undefined}\\ \mathrm{sec}t=\text{Undefined,}\mathrm{csc}t=-1,\mathrm{cot}t=0\end{array}$

## Finding the value of trigonometric functions

If $\text{\hspace{0.17em}}\mathrm{sin}\left(t\right)=-\frac{\sqrt{3}}{2}\text{\hspace{0.17em}}\text{and}\text{\hspace{0.17em}}\text{cos}\left(t\right)=\frac{1}{2},\text{find}\text{\hspace{0.17em}}\text{sec}\left(t\right),\text{csc}\left(t\right),\text{tan}\left(t\right),\text{cot}\left(t\right).$

$\text{\hspace{0.17em}}\mathrm{sin}\left(t\right)=\frac{\sqrt{2}}{2}\text{\hspace{0.17em}}\text{and}\text{\hspace{0.17em}}\mathrm{cos}\left(t\right)=\frac{\sqrt{2}}{2},\text{find}\text{\hspace{0.17em}}\text{sec}\left(t\right),\text{csc}\left(t\right),\text{tan}\left(t\right),\text{and}\text{\hspace{0.17em}}\text{cot}\left(t\right)$

$\mathrm{sec}t=\sqrt{2},\mathrm{csc}t=\sqrt{2},\mathrm{tan}t=1,\mathrm{cot}t=1$

## Evaluating trigonometric functions with a calculator

We have learned how to evaluate the six trigonometric functions for the common first-quadrant angles and to use them as reference angles for angles in other quadrants. To evaluate trigonometric functions of other angles, we use a scientific or graphing calculator or computer software. If the calculator has a degree mode and a radian mode, confirm the correct mode is chosen before making a calculation.

Evaluating a tangent function with a scientific calculator as opposed to a graphing calculator or computer algebra system is like evaluating a sine or cosine: Enter the value and press the TAN key. For the reciprocal functions, there may not be any dedicated keys that say CSC, SEC, or COT. In that case, the function must be evaluated as the reciprocal of a sine, cosine, or tangent.

If we need to work with degrees and our calculator or software does not have a degree mode, we can enter the degrees multiplied by the conversion factor $\text{\hspace{0.17em}}\frac{\pi }{180}\text{\hspace{0.17em}}$ to convert the degrees to radians. To find the secant of $\text{\hspace{0.17em}}30°,$ we could press

Given an angle measure in radians, use a scientific calculator to find the cosecant.

1. If the calculator has degree mode and radian mode, set it to radian mode.
2. Enter: $\text{\hspace{0.17em}}1\text{/}$
3. Enter the value of the angle inside parentheses.
4. Press the SIN key.
5. Press the = key.

Given an angle measure in radians, use a graphing utility/calculator to find the cosecant.

• If the graphing utility has degree mode and radian mode, set it to radian mode.
• Enter: $\text{\hspace{0.17em}}1\text{/}$
• Press the SIN key.
• Enter the value of the angle inside parentheses.
• Press the ENTER key.

## Evaluating the cosecant using technology

Evaluate the cosecant of $\text{\hspace{0.17em}}\frac{5\pi }{7}.$

For a scientific calculator, enter information as follows:

Evaluate the cotangent of $\text{\hspace{0.17em}}-\frac{\pi }{8}.$

$\approx -2.414$

Access these online resources for additional instruction and practice with other trigonometric functions.

what is subgroup
Prove that: (2cos&+1)(2cos&-1)(2cos2&-1)=2cos4&+1
e power cos hyperbolic (x+iy)
10y
Michael
tan hyperbolic inverse (x+iy)=alpha +i bita
prove that cos(π/6-a)*cos(π/3+b)-sin(π/6-a)*sin(π/3+b)=sin(a-b)
why {2kπ} union {kπ}={kπ}?
why is {2kπ} union {kπ}={kπ}? when k belong to integer
Huy
if 9 sin theta + 40 cos theta = 41,prove that:41 cos theta = 41
what is complex numbers
give me treganamentry question
Solve 2cos x + 3sin x = 0.5
madras university algebra questions papers first year B. SC. maths
Hey
Rightspect
hi
chesky
Give me algebra questions
Rightspect
how to send you
Vandna
What does this mean
cos(x+iy)=cos alpha+isinalpha prove that: sin⁴x=sin²alpha
cos(x+iy)=cos aplha+i sinalpha prove that: sinh⁴y=sin²alpha
rajan
cos(x+iy)=cos aplha+i sinalpha prove that: sinh⁴y=sin²alpha
rajan
is there any case that you can have a polynomials with a degree of four?
victor
***sscc.edu/home/jdavidso/math/catalog/polynomials/fourth/fourth.html
Oliver
can you solve it step b step
give me some important question in tregnamentry
Anshuman
what is linear equation with one unknown 2x+5=3
-4
Joel
x=-4
Joel
x=-1
Joan
I was wrong. I didn't move all constants to the right of the equation.
Joel
x=-1
Cristian
y=x+1
gary
x=_1
Daulat
yas. x= -4
Deepak
x=-1
Deepak
2x=3-5 x=-2/2=-1
Rukmini
-1
Bobmorris