Question about Casio FX-260 Solar Scientific Calculator 1 EA CSOFX260SOLAR

# The math problem is x2= 85-84 cos25 and it doesn't work on the fx-260

I have to use the cosine law but i don't know how to work with the calculator to get the correct answer which is 3. Please Help

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• k24674 Jan 22, 2013

If you take the square root of 8.87015 you get 2.978279705 which you can round up to 3.

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• Casio Master

85-84cos(25 deg)=8.87015 and I do not see how you get 3. If angle is in radians the answer is 1.73896. Make sure your calculator is configured to use the right angle unit (radian, degree or gradian).

Posted on Jan 20, 2013

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Posted on Jan 02, 2017

Posted on Feb 09, 2009

Hello,
To convert fractions to decimals or decimals to fractions, you use the [S<->D] key. Each time you press the key the result is displayed in the other format.
Alternatively, If you multiply or divide two integer numbers put a decimal mark at the end of one of the numbers (any one). The result will be displayed in decimal format.

Hope it helps.

Posted on Sep 12, 2009

Hello,
I am only looking for a plausible cause of the error, because I do not believe your calculator can make such a mistake. I think you accidentally activated the Exponential display format and did not pay attention to the small, raised -03 that came at the end of the number displayed. It is a common mistake for those not very familiar with Scientific or exponential notation.

Let us try to reset your calculator to the normal (floating point) format.
Press the [MODE] key a number of times until you reach a screen that has FIX, SCI, NORM and under each one a number (FIX 1, SCI 2), Norm 3). To have the number of decimal place you gave in your result (4 decimal digits), you press 1 to select Fix then 4.

Be aware that scientific calculators usually stop displaying results in floating point format ( 0.0000045 ) if the number is smaller then 0.001. So basically, 0.00099 will be displayed as 9.90-04, -04 being raised above the level, and in smaller size.

Hope it helps.

Posted on Oct 02, 2009

Testimonial: "Thanks so much, its working now:) I thought I was going to have to buy a new calculator!"

Hello,

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.

Posted on Nov 05, 2009

General shortcut.
If the concentration is of the form 1* 10^ (-a) where a is an integer between 0 and 14, the pH is given by a.
c= 1.* 10^(-5), pH=5
c=1.*10^(-11(, pH=11.

For other values, ex: c=3.68 *10^(-8)
pH: 3.68 [EXP] [+/-] 8 [LOG] [+/-] Result is 7.434
Above, the [+/-] key is the change sign key, just above the [7] key.

Posted on Mar 16, 2010

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