20 Most Recent Casio FX-115ES Scientific Calculator - Page 2 Questions & Answers

HelloPress SHIFT then MODE then press either 6 to specify a fixed decimal notation or 8 to specify floating decimal notation.Hope this helps

This post is rather exhaustive as regards the matrix capabilities of the calculator. So if the post recalls things you already know, please skip them. Matrix multiplication is at the end.

Let me explain how to create matrices. (If you know how to do it, skip to the operations on matrices, at the end.)

First you must set Matrix calculation
[MODE][6:Matrix]. Then By entering one of the numbers [1:MatA] or [2:Matb] or [3:MatC] you get to choose the dimensions of the matrix
(mxn]. Once finished entering the matrix you clear the screen.
The operations on matrices are available by pressing [Shift][Matrix]
[1:Dim] to change the dimension of a matrix (in fact redefining the matrix)
[2:Data] enter values in a matrix
[3:MatA] access Matrix A
[4:Matb] access Matrix B
[5:MatC] access matrix C
[6:MatAns] access the Answer Matrix (the last matrix calculated)
[7:det] Calculate the determinant of a matrix already defined
[8:Trn] The transpose of a matrix already defined

To add matrices MatA+MatB (MUST have identical dimensions same m and same n, m and n do not have to be the same)
To subtract MatA-MatB. (MUST have identical dimensions, see above)
To multiply MatAxMatB (See below for conditions on dimensions)
To raise a matrix to a power 2 [x2], cube [x3]
To obtain inverse of a SQUARE MatA already defined MatA[x-1]. The key [x-1] is the x to the power -1 key. If the determinant of a matrix is zero, the matrix is singular and its inverse does not exit.

Dimensions of matrices involved in operations must match. Here is a short summary

The multiplication of structured mathematical entities (vectors, complex numbers, matrices, etc.) is different from the multiplication of unstructured (scalar) mathematical entities (regular numbers). As you well know matrix multiplication is not commutative> This has to do with the dimensions.

An mXn matrix has m rows and n columns. To perform multiplication of an kXl matrix by an mXn matrix you multiply each element in one row of the first matrix by a specific element in a column of the second matrix. This imposes a condition, namely that the number of columns of the first matrix be equal to the number of rows of the second.
Thus, to be able to multiply a kXl matrix by am mXn matrix, the number of columns of the first (l) must be equal to the number of rows of the second (m).

So MatA(kXl) * MatB(mXn) is possible only if l=m
MatA(kX3) * Mat(3Xn) is possible and meaningful, but
Mat(kX3) * Mat(nX3) may not be possible.

To get back to your calculation, make sure that the number of columns of the first matrix is equal to the number of rows of the second. If this condition is not satisfied, the calculator returns a dimension error. The order of the matrices in the multiplication is, shall we say, vital.

It's a bit convoluted, and it only works for integers, but here's one way. Press MODE 4 to switch to BASE-N (integer) mode. If the screen doesn't read "Dec" then press the x^2 key. Now, to calculate a mod b, calculate a-a/b*b. No shortcuts, no rearranging. That's a minus a divided by b times b. You have to enter both numbers twice, but you will get the modulus.

Press MODE 1 to return to your previously scheduled calculations.

Just order 2 larges.

its simplepress mode3;stat2;A+Bxl x l y l l 2 l 4.6 l l 4 l 5.9 l press; ACpress;5.9press; shiftpress;1press;7 (reg)press;5 (comma)press;=u will get ans

it seems the problem is on the lcd. technicians usually use soldering iron to apply heat to the cable connecting the lcd to its mainboard.

Just divide them normally. The result will appear in whichever complex display format you have selected.

1 1 0 SHIFT (-) 0 / ( 5 0 + 8 0 ENG ) =

Don't leave out the parentheses, or you'll get (110 angle 0 divided by 50) plus j80.

Here it is.

Actually, the answer is 79.

The fx-115ES does not have a key for the modulus operation. Nor does it have an integer-part or fractional-part operation. However, it is possible to calculate the remainder using integer arithmetic.

Press MODE 4 to shift into integer mode. Then type in 3 5 2 - 9 1 * ( 3 5 2 / 9 1 ) = and see the answer 79. It's a pain as both numbers have to be entered twice, but it does get the job done.

To get back to working with real numbers again, press MODE 1 ( or MODE 2 for complex).

Let x be the number of future weeks. 8 + 4x >= 30 Solve for x by subtracting 8 from each side and dividing by coefficient in front of variable. Plug answer into original equation to check that it works correctly. Good luck, Paul

Let your system of linear equations be [A][X]=[B] where [A] is a 3x3 matrix, [X] is column vector ( a 3x1 matrix) , and [B] is also a column vector or (3x1) matrix.

Assuming you are able to invert the [A] matrix to find [A^-1].
Multiplying on the keft by [A^-1] the system of equations you get
[A^-1].[A][X]=[A^-1][B].
But since the product [A^-1][A] is the (3x3) Identity matrix, the left side of the equation is jut [X], while the right side is [A^-1][B]. As you can see it is not [B][A^-1] .
To solve your problem, you should define your [A] matrix, define the [B] column vector (3x1) matrix, then perform the operation [A^-1][B] using the [X to -1] power key to calculate the inverse [A^-1].

Haven't heard of it giving nearest whole numbers before. But have you tried pressing SHIFT and then SETUP (upper right hand corner next to ON button) and then pressing 2 (LineIO)? Or perhaps you're in different MODE?

You can use the replay button to display the last command entered, then move cursor to the end of the command line and append the part you want to add. But it must be a part of the same command line, with correct syntax. As to the last result calculated, it is stored in ANS memory. It will be overwritten by the new calculated value.

Here check the manual:

http://support.casio.com/manualfile.php?rgn=5&cid=004001004

The FX-991ES offers simple matrix operations like basic arithmetic, plus the slightly more complex operations determinant and inversion. Furthermore, it is limited to matrices with a maximum size of three rows and three columns.

The rank of a matrix is defined as the number of linearly independent row or column vectors. You can perform a simple partial test for square matrices by calculating the determinant of the matrix:

1. Enter the matrix into matrix variable MatA.
2. Press [SHIFT] [4] [7] [SHIFT] [4] [3] [)] [=]

The display now should show det(MatA) and the determinant of the matrix in the result. If the determinant is not 0, the rank of the matrix equals the dimension of the matrix, otherwise the rank is less than the dimension.

Unfortunately, this is all support the calculator offers. For small matrices (i.e. 4x4 or smaller), you should familiarize yourself with the Gau? Elimination Method algorithm for solving linear equation systems. It is a two-step procedure where a matrix first is converted to its row echelon form, and second to row canonical form to solve the LES.
You need to follow the algorithm only through the first part, the number of non-zero rows after this step equals the rank of the matrix. With a little exercise you will be able to do it faster on paper than trying to do it with your calculator only.

For larger matrices I suggest to use a PC with more powerful math software (Maple, Mathematica, ...) or, if you know some basic computer programming, just write the necessary program yourself, which is also a very good exercise both in programming and understanding the algorithm.

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.

Page E-3 of the manual. Press the ALPHA key and then the key to input the applicable variable, constant, or symbol. You can download the manual from here: http://support.casio.com/storage/en/manual/pdf/EN/004/fx-115_991ES_PLUS_C_EN.pdf

Press SHIFT SETUP 1

With log a / log b = loga (b) formula

In casio for log2 8 = log8 / log 2 = 3