For some reason, it won't graph sin/cos/tan properly..for example, the graph of sin comes out with a straight line..how do I fix this?
Make sure you have the angular mode set to radians. In degree, the graph of sine(x) is nearly a straight line for small values of x.
SOURCE: TI-84 Incorrect sin/cos/tan values
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.
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.
SOURCE: SIN COS TAN
The answer that you have received in actuality is correct. However, it is in exact form when the answer that you were looking for was an approximation (decimal form) answer. To achieve this all you have to do is hit the alpha button (the yellow button with a diamond in the center) and then enter which will give you your desired answer :-)
SOURCE: TI-84 Plus silver edition sin/cos/tan
for function = (sin,cos,tan,sec,cosec,cotan)
arc(function) = function^-1, calculated in the first quadrant for simplicity(0-pi/2) (0-90deg), as all functions repeat circularly
just another method of notation
http://www.mathwords.com/t/tangent_inverse.htm
SOURCE: Hey, Recently, I've been trying to
Having gone over a month without a response to my query, I assume it was a matter of the angular mode setting
SEC, CSC & COT are the INVERSE of COS, SIN & TAN and are usually require hitting the "2nd F" or "Func" key of the calc to make:
SIN button work as COSEC,
COS button work as SEC
TAN button work as COT
Formulas are below:
sec x = 1
cos x
cosec x = 1
sin x
cot x = 1 = cos x
tan x sin x
Good luck!
Let's start with a little background.
The cot(x) is also known as the cotangent(x) and it equals 1/tan(x) which equals cos(x)/sin(x). I'm showing these formulas because your calculator may not have a cot button but it will probably have buttons for tan, cos, and sin.
Your calculator may also have buttons for tan-1, cos-1 and sin-1. These are the inverse functions for tan, cos, and sin. If you enter a number and then push the tan-1 button, the result is the angle whose tangent is the entered number. For example, it you enter 1 and push the tan-1 button the answer will be 45 deg because tan (45 deg) = 1.
Now let's look at the problem, cot(x) = -0.6.
The first thing we need to know is do you want the answer in degrees or radians? Your calculator will have both modes. The default mode when you first turn it on is probably degrees. If this problem is in radians you will need to change the mode of your calculator over to radians before we start.
If cot(x) = -0.6, then tan(x) = 1/-0.6 from the formula I showed in the background section.
This means tan(x) = -1.6666666...
Now we just enter -1.66666667 and hit the tan-1 button to get the answer.
If we're operating in radians the answer is -1.0307 radians.
If we're operating in degrees the answer is -59.036 deg.
I hope this helps you out.
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