How to save formula in casio fx 991 es calculator

Sorry, but this calculator does have the EQN calculation mode. Try the FX-991 ES.

The Casios FX-115 ES , FX-115 ES PLus, FX-991 ES, FX-991 ES Plus C can perfom numerical differentiation at a point, and numerical integration between two given limits.

Sorry, the Fx-115W is unable to solve equations of any type. In addition to that, the more sophisticated Casios such as the FX-991 ES solve linear equations of no more than 3 variables.

Casio has a scientific calculator with Model FX-991 ES. It is sold in North America, and maybe in other continents. You can find it at Staples/ Bureau en Gros stores for around 29 CAD.

Sorry, but you cannot.
You can type in a formula that involves the memory variables X,Y, A, B,C,D, E, =, . Such a formula is meant to be evaluated to get a solution (X by default). Once you type the formula you press the Shifted function SOLVE and you will be prompted for the constants, for Y etc. when you press the EXE/= key you get the value of X.
If you turn off the calculator or change the calculation MODE, it is wiped out of memory.

To make a long story short, you cannot STORE formulas in the calculator. Better try to memorize them (commit then to YOUR OWN memory).

its simple
press mode
3;stat
2;A+Bx
l x l y l
l 2 l 4.6 l
l 4 l 5.9 l
press; AC
press;5.9
press; shift
press;1
press;7 (reg)
press;5 (comma)
press;=
u will get ans

For common logs (logs in base 10) use the 10^x function : Press [SHIFT] [Log] to access it.
For natural logs, use the exponential function. Press [SHIFT][ln] to access it.

The enclosed screen capture shows all the possible dimensions for matrices on the Casio FX-991ES. As you can see the maximum dimension of any matrix is 3. You can only create matrices with dimensions less than or equal to 3.

Hello,

There are many different functions...

You can download the entire manual after answering a few questions at www.safemanuals.com

after using the dropdown menu for this make and model.

Good Luck!

Hello,
Sorry I clicked the post a clarification request too fast.

You cannot compute it directly. You have to use the formula

log_18(number) = ln(number)/ln(18).

Here log_18 is log in base 18, ln is the natural logarithm (naeperian or log in base e).

Alternatively, you can use

log_18(number) = log(number)/log(18)

where log is log in base 10.

If you use those types of calculations a lot, it might be a good idea to get a Casio FX-115ES, or a Casio FX-991 ES. They have other nice features like fraction calculations and radicals.

Hope it helps.