I keep getting wrong answers with the radians mode on. What i typed in was cos(20π + (π/2)) and I get a weird answer (-1E-13) when i know the answer should be zero because i did it on another calculater and that's what i got. Please help me, i have no idea what could be wrong because with other specific things (sin( 20π + (π/2)) for example) ive typed in it does give the right answer, but i don't know why with the other one it doesn't.
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When the angle unit is in radians
When angle unit is in degrees
Your calculator is calculating the functions correctly)
In the following screen captures the sine of the values is calculated with the unit specified inside the formula (degree symbol and radian symbol are inserted to show you the unit). In the last calculation the value of the sine is practically 0.184 Remember that when angle is in radians, for very small angles (less than 10 degrees), sin(x) and tan (x) are about equal to the value of the angle in radians
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.
Put the calculator in radian angle mode. The top answer is in AUTO mode and, The bottom is in Approx mode.
I converted 60 degrees into pi/3 radian which equals 1.0472 radians. I figured 5 significant digits was good enough since, you only went 4. If you have any question just post them and, I'll respond quickly.
Check to see if you are in radian mode or degree mode (one of the top categories)
If you are entering your numbers from sin, cos, and tan as degrees and you are in radians, your answers will be off.
Same goes for if you are inputting radians while in degree mode.
Hope this helps
Most likely you do have the calculator in radians (or if you are working in radians, you have it in degrees). Press the mode button, move cruser down to "radians degrees" highlight degrees. and press "2nd quit". things sould be better!
Hello, That habit of TI, Casio, and Sharp to label the inverse trigonometric functions with the -1 superscript can cause confusions.
The inverse trigonometric functions arcosine, arcsine, and arctangent (labeled by manufacturers as cos^-1, sin^-1, and tan^-1) should not be confused with the other trigonometric functions known as secant(x) =1/cos(x), cosecant(x)=1/sin(x) and cotangent(x) = 1/tan(x).
To avoid errors in the use of the inverse trigonometric functions, one must be careful and set the angle unit to the one required by the problem at hand (degrees, or radians)
To make the trigonometric functions really functions, their range is restricted.
In this calculator arcosine (x) gives results between 0 and 180 degrees (if angle MODE is Degree) or between 0 and Pi radians (if angle MODE is Radian).
The range of results for arcsine(x) and arctangent(x) is between -90 degrees and +90 degrees (if angle MODE Degree) or -Pi/2 and Pi/2 (if angle MODE is Radian)
With this information you should be able to set the angle unit correctly ([MODE][Radian] or [MODE][Degree] ) and interpret the results. If you want to extend the angle to other values, use the periodicity of the trigonometric functions.
Hello, It may be due to the angle unit used. You can have angles in degrees, in radians, and in grads. You should set the default angle unit to waht you problem calls for. To set degree as default SHIFT MODE 3 To set radians as default SHIFT MODE 4 To set grads as default SHIFT MODE 5
The values of angles calculated by the inverse trigonometric functions are in the default unit that is set . This may be the source of the wrong answers that you get.
To avoid problems,set your angle unit to radians by default. Press [MODE]. If Radian is highlighted (text on black background), it is indeed the default mode. If Degreee is highlighted, scroll dowm to the line and use the left arrow to select Radian and press ENTER. Radian will start blinking.
Any number you feed a function that acts on angles (sin, cos, tan) will be considered in radians. Any result that comes out of the inverse trigonometric functions (arcsin, arccos, arctan) is in radian. The angle coming from a conversion from cartesian coordinates to polar coordinates is in radian.
You have a simple way to convert the value from radians to degrees because 1 rad=180/pi. Store this value in a variable [STO->] D 180/[2nd][PI] [STO->] D
Since the last result is always stored in [Ans] all you have to do is to multiply by D: [Ans][x][ALPHA]D converts results in degrees.
Your calculator is set in radians. Press mode key. Arrow down to 3rd line. Highlight degree and press enter. Your calculator is now in degrees, not radians. To get out of the mode screen and back to home screen, press 2nd and then mode.