My new calculator is giving incorrect answers to sin, cos, and tan problems. Is there a setting I need to switch to? For example, sin -1 (.423) = .4367 not 25 degrees

Contact maker's Customer Support direct.

https://education.ti.com/en/products

..

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.

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.

Make sure you have the proper angular mode set. The TI-84 can work with degrees or radians.

Press MODE to bring up the mode screen. Use the arrow keys to highlight either "Radian" or "Degree" on the third line and press ENTER. Press 2ND [QUIT] to exit the mode screen.

If this doesn't do it, please reply to this post giving an example of a calculation and the answer you're getting from the calculator.

The FX-115ES is somewhat different to other calculators you might know. The sequence of keys is more like writing up a calculation in a textbook, whereas for "normal" calculators operations are reversed in some places.
For example, with most calculators you would type 30 [sin] to calculate the sine function of 30 degrees, with the 115ES its [sin] 30 [=].

The 115ES has all the standard trigonometric functions:

• Standard functions (sin, cos, tan), type the [sin], [cos] or [tan] key followed by the argument.
• Inverse trigonometric (sin?¹, cos?¹, tan?¹), type [SHIFT][sin], [SHIFT][cos] or [SHIFT][tan] followed by the argument.
• Hyperbolic functions (sinh, cosh, tanh), type [HYP][sin], [HYP][cos], or [HYP][tan] followed by the argument.
• and finally inverse hyperbolic (sinh?¹, cosh?¹, tanh?¹), its [SHIFT][HYP][sin], [SHIFT][HYP][cos], or [SHIFT][HYP][tan] followed by the argument.

Arguments can be given as numbers with mantissa (2.718), as fractions (use the fraction key below [CALC]) or as degree, minute, second (30°12'45") using the [°'"] key for input. To switch between degrees (1 circle = 360°), radians (1 circle = 2?), or grad (1 circle = 400 gon), use [SHIFT][DRG>].

Hello,
You have 3 keys for the main trigonometric functions: [SIN], [COS] and [TAN]
To use them correctly you must set the angle unit to the one your problem calls for.
Press [SIFT][MODE] [3:Deg] for degree, [4:Rad] for radian, [5:Grad] for grad. Dependig on angle unit chosen a small D, R, or G appears on the top of the screen.

If you need the inverse trigonometric functions arcsine, arccosine, arctangent, you access them by first pressing the [SHIFT] key
Thus
arcsine [SHIFT][SIN] (sin^-1)
arcosine [SHIFT][COS] (cos^-1)
arctangent [SHIFT][TAN] (tan^-1)

The syntax for the function is
[SIN] # [ ) ] [=]; [SIN] 30 [ ) ] [=] gives 0.5
[COS] # [ ) ] [=] [COS] 19 [ ) ] [=] gives 0.945518576

Note: if the argument of the functions are numbers, the right parenthesis is not necessary. But if the argument is an expression (with various operations) better put the parenthesis to make sure the calculator is performing as one wants it to.

By the way, there are no keys, or key combinations to calculate cotangent, cosecant, and secant, but you can use the definitions:

cotangent (x) = 1/tan(x) Do not confuse it with tan^-1
cosecant(x) = 1/sin(x) Do not confuse it with sin^-1
secant(x) = 1/cos(x) Do not confuse it with cos^-1

Hope it helps.

You should buy a dog that takes you on walks.
Then you won't have the problem that you have.

go to:


mode
select DEGREE rather than RADIAN three lines down.

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 :-)

here are the steps in changing it from radian to degrees
1. turn on your TI-83 plus
2. press the MODE button near the top of your calculator
3.go down to options and move the highlight from radian to degree, press enter and clear
you're good to go