How do I fix the sin on my calculator?

Press 2nd SIN

For example, to calculate the inverse sine of 0.5, press 2nd SIN . 5 =

The position of the exponent in trig functions is an anomaly in mathematical notation. While the square of sin x is commonly written as
sin^2(x) ,
the square of any other function is written as f(x) ^2 . For example, you wouldn't write ln^2(2) if you mean the square of the natural logarithm of 2, instead you write it as ln(2)^2 or (ln(2))^2 .
The calculator works the same way. To calculate the square of the sine of 3, for example, press
SIN 3 ) ^ 2 ENTER

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.

Of course. Just press the INV key before pressing the appropriate trig function key. For example, to calculate the inverse sine, press INV then sin.

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>].

The sine of 6pi is indeed zero. The calculator works with twelve decimal digits while pi is an irrational number with an infinite number of decimal digits. Thus the calculator cannot actually calculate the sine of 6pi, instead it calculates the sine of 18.8495559215. The sine of that number is close to zero but not quite, about 0.000000000002 which is what the calculator shows. This is a natural consequence of using finite machines to deal with infinite numbers.

In degrees, 3*360 is 1080 exactly and thus the calculator can produce an answer of exactly zero.

You'll notice that the calculator also gives a nonzero result for the sine of 4pi.

The "proper" fix for this is something called "argument reduction." If the argument lies outside the range of 0 to 2pi (or alternatively, the range -pi to pi), add or subtract multiples of 2pi until the argument is inside the range. So in this case, subtract 6pi from 6pi to get zero, then take the sine of that.

Bear in mind that argument reduction won't always work, since it too is limited to twelve-digit arithmetic.

First, make sure the calculator is set to degrees (2nd [FORMAT] down-arrow).

Put in the value, press INV, the appropriate function key, and =.

For example, to find the inverse sine of .3, press
. 3 INV [SIN] =

The cosecant function does not have a specific key on any calculator because it can be easily calculated as the reciprocal of sine.
Thus csc(-330°)=1/sin(-330°)=2
sin(-330°)=sin(360°-330°)=sin(30°)=0.5
csc(-330°)=1/0.5=2
If you do not want to be bothered with these facts, just calculate the sine of -330° and take the reciprocal of the result using the [x^-1] key. For the minus sign before 330, use the change sign key (-). Close the right parenthesis.

[SIN] [(-)] 330 [)] [x^-1]

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

Put the calculator in radian mode. Find the sine of the angle (sin(angle)), invert the result (1/x or x^(-1)). csc = 1 / sin