Can I figure Sine, Cosine and Tangent on my TI-15?

Not quite true. (Explanation at the end)
The sine and cosine of an angle have values in the closed interval [-1,1]. That means whatever the value of the angle, its sine or its cosine cannot be less than -1 or greater than 1.
When you consider the inverse problem where you want to find the angle whose sine or cosine is known, you must take the values of the sine or cosine in the interval [-1,1]. That is the domain of the functions arc sine and arc cosine. So if you take a value outside the domain [-1,1], and want to calculate the angle to which it belongs, the calculator signals that there a domain error, because there is no angle that answers the question. Limit the arguments of the sin^-1 and cos^-1 to values in [-1,1]
For the inverses of arc tangent and arc cotangent functions there is no domain limitation because the range of tangent and cotangent is the whole real line ]-infinity, +infinity[.

Not directly. The calculator does not have the trig functions built in. You could do it the same way people did it before pocket calculators.

What do you want to do with it? Convert an angle in degrees to radians? Calculate its sine, cosine, tangent, or other trigonometric function? Convert a temperature in degrees Celsius to degrees Fahrenheit or vice versa?

You have to go to DEGree mode. See captured image

Sinus, cosinus, and tangens (Latin names) are the same as sine, cosine, and tangent (full English names), which are abbreviated to sin, cos, and tan. If you're asking how to use these functions, they deal with right triangles and finding the missing angles or side lengths of the triangle.

Always, sine equals opposite/hypotenuse, cosine equals adjacent/hypotenuse, and tangent equals opposite/adjacent.


Using this picture, the sine of angle A equals a/c, the tangent of angle B equals b/a, and the cosine of angle A equals b/c, and so on.

In a calculator, simply hit the desired function (sin, cos, or tan), then in parenthesis put the measure of the angle, and then use what you know about the triangle to find out the rest.

Unlike traditional calculators, the FX9750G uses textbook order to call functions. For example, to calculate the sine of 45°, you key in (angle argument unit set to degrees assumed):

[sin] 45 [EXE]

Cosine and tangent are analogous. Argument format can be degrees, radians or grad. You can set up the angle argument unit by keying in:

[SHIFT] [SETUP] [v] [v] [v] [v] and then

• [F1] (Deg) [EXIT] for degrees (1 full circle = 360°),
• [F2] (Rad) [EXIT] for radians (1 full circle = 2pi),
• [F3] (Grad) [EXIT] for grad (1 full circle = 400 gon).
  

Since you are familiar with sines, cosines, you know that their ranges (interval of values) varies from -1 to 1. The inverse functions of sine and cosine tkae their values in that very domain, [-1,1].
However you fed the arc sine function (sin^-1) a vlaue of (25/20.48) and that value is obviously larger outside the [-1,1] domain, hence the DOMAIN error message.

No such domain limitations exist for arc tangent (tan^-1) because the range of the tangent function spans the open interval ]negative infinity to positive infinity[.

Formulas relating to right angled triangles are:
Sine = perpendicular divided by hypotenuse
Cosine = base divided by hypotenuse
Tangent = perpendicular divided by base
Sine Tangent and Cosine functions are all available in Excel

Hello,
I believe you are not pressing the keys in the right order.
If you know how to set angle unit, skip this part and go to Exemples

If you want to calculate the sine , cosine or tangent of an angle given in degrees, the calculator must have the angle unit set to degrees. To do so :Turn calculator ON, scroll to [RUN] icon and press [EXE] then [SHIFT][SETUP]. On the fifth line angle must be set Degrees. If it is not in degrees, press the key correspondig to menu deg (F1)
(If you have to use the Radian as unit of angle, that is where you set it.)
So your angle is in degrees.
Exemples
To calculate the sine of 15 degrees press [SIN] 15 [EXE].
If expression inside the sine is complicated or contains diverse operations use parentheses as in the exemple
[SIN] [(] 90/2 -180/3 [)] [EXE].
You proceed the same way for cosine, or tangent.

Hope it helps.

you're in radians...
go to MODE
scroll down twice
hit the right button
then hit enter...  :)