Calculation with angle

Hi there,

To use the trig functions simply press the button with the trig function you want and then type in the value of the angle. If you want to add or subtract thing within the angle remember to put open and close ( ) brackets around the angle.

If you have any other calculator questions dont forget to check out Welcome to Maths at SHARP Maths at Sharp

The website also has a manual available to download.

You need more information to be able to solve resolve the triangle.
All you can say is that the sum of the measures of the two unknown angles is
sum of values of the two angles =(180-76) degrees.

To calculate the Cosine of an angle, you first make sure that the angle unit on your calculator is set to the correct one (degree, or radian). After that it is all simple. Enter the angle value (50 degrees) then press the [COS] key. If you get an error then press the COS key followed by the angle value then press =.
Note if your calculator display Cos ( , with a left parenthesis, then you have to press COS first followed by the angle value and possibly the right parenthesis.
Note. The theta here is of no relevance.

When you use trigonometric functions you should always make certain that the angle unit the calculator is configured for is the intended one.
When the unit is set to degree sin(37)=0.6018
When the angle unit is set to radian, sin(37 rad)=-0.6435

Change the angle unit to degree.

1. Press the MODE button
2. Scroll to reach the Angle line.
3. Use right arrow to highlight deg and press ENTER to validate.

Press the relevant function key [SIN],[COS],[TAN] followed by the angle value.
For inverse trigonometric functions [SIN^-1], COS^-1], or [TAN^-1], Press [SHIFT][SIN], [SHIFT][COS], or [SHIFT][TAN].
For other functions
sec(x)=1/cos(x)
csc(x)=1/sin(x)
cot(x)=1/tan(x)

When calculating trigonometric functions one must make sure that the angle unit the calculator is using is the correct one.

What is so surprising? The sine and cosine functions have ranges that span the closed interval [-1,1]. As to the tangent function, its range is the the whole real line.

This being said, you should keep in mind that there are three angle units: the degree, the radian, and the grad.
When you want to calculate the sine, cosine, or tangent of a number, that number is not just a number. It is an angle, and as an angle it has a unit.

For this reason a calculator generally has two angle units defined (degree and radian), and possibly the grad. BEFORE calculating any trigonometric function you must ascertain that the angle is in the correct unit.

Clearly, in the problem you are trying to solve angle values are given in degrees, but your calculator is configured to interpret angles values in radians.

To set the default angle unit to degree press [MODE] , then press down arrow twice to reach the line (radian, degree). Highlight the word degree and press [ENTER] to set the default angle unit to degree.

Unfortunately the TI 8xPLUS family of calculators does not have a status bar on screen to remind you of the modes, and if you do not remember to check the current unit you get errors (at least unexpected results).

However, there is a way to avoid the errors and that is to enter the unit explicitly after the angle value. To do that you press [2nd][APPS] to open the (ANGLE) menu list. Try it.

1. First item in list is the degree symbol, a raised 0
   
2. 2nd is the minute, an apostrophe
   
3. 3rd is radian, a raised r
   

By selecting the degree symbol and pressing [ENTER}, that symbol echoes on the screen just after the angle value. Closing the right parenthesis of the trigonometric function and pressing [ENTER] will give you the result in the correct unit of your choice. This can be done regardless of the default unit the calculator is configured for.

Hello,

Before starting to enter the angle measure to calculate the value of a trigonometric function (sine, cosine, tangent) you must make sure that the current angle unit (degree, radian, grad) the calculator is configured to be using is the same that your problem requires. For instance, if you are solving a problem in which the angles are given in degrees you must verify that the calculator is configured to work in degrees.

When calculator is turned on, the angle unit is reset to degrees, but just to make sure it still is, look at the display: It should show the indicator DEG. If the display indicator is not DEG press the key [DRG] once or twice until you see the DEG on the screen.
The angle unit being taken care of, we turn to the actual calculation
Usually, to calculate the sine of an angle, you enter the angle value, press the [SIN] key and hit [=]. As you can see the sine function eats the number stored in its current register and calculates its sine.

To make sure that the calculator is taking the sine of 65 and not of 25*65, I would enter the calculation as follows
[65 [SIN] [*] 25 [=] : the result should be 22.65769468
or
25[*][ ( ] 65 [SIN] [ ) ] [=]

In the last key sequence, the use of parentheses forces the calculator to pause all previous calculations and wait for the closing right parenthesis. When the right parenthesis is entered, the calculator takes care of the contents of the parentheses first, then resumes the operations entered before the parentheses.

Importance of checking the angle unit before a calculation

Let us perform the calculation with angle unit

1. in degrees : 25* sin(65) = 22.65769468
2. in radians : 25 *sin(65) = 20.67071699

As you can see, the two values are not very far apart and since you are expecting a value that does not exceed 25 you might want to check your result.

Hope it helps.
Thank you for rating this solution

Hi,
The source of errors is most certainly due to the wrong schoice of angle unit (degree or radian). If the default angle unit set in your calculator is the degree, any value fed to the trigonometric functions (sin, cos, tan) is considered to be expressed in degrees. Consequently, if you calculate the arctangent ( tan^-1) of a value, the angle returend by that inverse trigonometric function is expressed implicitly in degrees.

Similarly if radian is the default angle unit in your calculator, any angle returned by an inverse trigonometric function (arcos, arcsin, arctan) is in radian.

Set the default angle unit as the one required by your problem at hand. This way, the angles returned will be in the right unit and you will not have a problem of interpretation.

Hope it helps.

Hello,
Check this article. It will show you how to force the reinstallation of the OS. If that does not solve your problem, you may have to send calculator for service.

Hope it helps.

inverse sine (sin^-1) gives you the angle when the opposite side length and the hypotenuse, in relation to that angle, are given. therefore, if you want to do sin^-1(x), 0<x<1 for all real triangles ex. sin^-1(1/2) would equal 30. if you get a decimal, then go to [Mode] and select degrees instead of radians to get angle measures instead of radians... :)