Sin cos tan

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.

log - logarithm abs - absolute value
hyp - hyperbolic function sin - sine cos - cosine tan - tangent rcl - recall variable value m+ - memory in eng - engineering notation

The trigonometric function [SIN],[COS] and [TAN] have inverse functions arc-sine, arc-cosine, and arc-tangent which are also implemented on scientific calculators. To access the inverse trigonometric functions you use the sequences [SHIFT][SIN], [SHIFT][COS] and [SHIFT][TAN]. The functions are marked on the body of the calculator as [SIN^-1], [COS^-1] and [TAN^-1].
When you use these functions, make sure that the angle unit is correctly set (as required by the problem you are solving) because the angle values returned are in the same unit as the one set.

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>].

By definition

1. cosecant of X =1/sin(X), must not be confused with arc sine [sin^-1]
   
2. secant of X =1/cos(X), must not be confused with arc cosine [cos^-1]
3. cotangent of X =1/tan(X), must not be confused with arc tangent [tan^-1]

Because of these simple relations, calculator makers do not implement them with specific key sequences.
On this calculator, you have two ways to calculate one of these functions. EX cosecant of 37 degrees

1. You enter 1 / [sin] 37 [ ) ] [ENTER] result is 1.661640141
2. You enter [sin] [ ) ] 37 [ENTER] followed by [X^-1] to take the reciprocal of the previous answer. The [X^-1] key is the one just below [MATH].

A word of caution: secant cosecant and cotangent must not be confused with the inverse trigonometric functions arcsin, arccos, arctan

Hello,
1.Set the correct angle unit required by your problem: degrees, radians, or grads. [SHIFT][MODE] [3:deg] or [4:Rad]

2. Press the key for the function COS, SIN, or TAN
[COS] displays Cos(

3.Enter the angle 12 deg Screen shows cos(12
Close the right parenthesis ) Screen shows cos(12)
4.Press [=] Screen displays 0.9781

If you want the inverse trigonometric functions you access them with arccos [SHIFT] [COS] (cos^-1)
arcsin [SHIFT][SIN] (sin^-1)
actan [SHIFT][TAN] (tan^-1)

You have to know the principal domain for the inverse trigonometric functions (see any book on trigonometry) to understand the results.
Hope it helps.

Hello,
There are no dedicated keys for these trigonometric functions, for the simple reason that they can be obtained from the tan, sin, and cos by a simple division.
cotangent (x) =1/tan(x) . Do not confuse with the arc tangent tan^(-1)
cosecant (x) = 1/sin(x) . Do not confuse with the arcsine sin^(-1)
secant(x) =1/cos(x) Do not confuse with the arccosine cos^(-10)

If you know how to use the tan, cos, and sin, with angle unit in degrees or radians, then there will not be any problem

If angle unit is degree, any number you give a trigonometric function is interpreted as degree. For instance if mode is in degree , and you calculate cos(PI) do not expect the value -1. You will have the value corresponding to the cosine of of 3.14159 degrees, namely 0.99849715

Now for you if you are interested.
If [MODE] is in degrees you can still enter angles in radians
You use the [2nd][ANGLE] [3: raised r] [ENTeR].
Here is a screen capture to show you more clearly.


The raised r is obtained by [2nd][ANGLE][3: raised r] [ENTER]

Hope it helps.

Hello,
What you deplore is perfectly normal.
7/60= 0.1166666667 the last 6 has been rounded to 7 (result is periodic)
36 + 7/60= 36.1166666667
36.7 -36-7/60=0.8166666667
tan(36 + 7/60) = 0.7296582051

Compare the tangents of two close numbers
tan(36.7)= 0.7453770282
tan(36.66666667)=0.7444724166

True, the precision of calculator is limited, but the number of digits it can display has a lot more precision that real-life problems really require.

Hope it helps.

Hello,
I have not yet seen a calculator that has a dedicated key for the cosecant , secant, nor cotangente functions, because they are directly connected with the sine, the cosine, and the tangente.

Cosecant (x) = 1/sin(x)
Secant (x) = 1/cos(x)
Cotangente(x) = 1/tan(x)

Do not confuse these functions with the inverse trigonometric functions, usually represented as
arccosine = arccos; on calculators cos^-1,
arcsine = arcsin ; on calculators sin^-1
arctangent= arctan ; on aclculators tan^-1

Hope it helps.

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