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I can't use an imaginary number in a sigma notation

I am trying to find a sigma notation, x=1 the index notation, ending number( number of terms) is 4, and where you fill in x is (2i+6)

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The summation function only works in the real mode, not the complex mode. You'll find that the same limitation applies to many other functions, such as the integration.

See page E-42 of this manual for the functions that are allowable in complex mode.

Posted on Apr 19, 2013


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1 Answer

How to do sigma notation?

The calculator cannot add the terms of a sequence. You need a graphing calculator that has that feature, or a calculator with a CAS (Computer Algebra System).

Aug 10, 2014 | Casio FX-270W Calculator

1 Answer


For arithmetic with complex numbers, treat the i as a named variable, and keep in mind i * i = -1 for multiplicative steps (not needed for this special case). I'll demonstrate in small steps, more than I'd do normally:

(3 - i) + (1 - 2i)
= 3 - i + 1 -2i [associative law]
= 3 + 1 - i - 2i [commutative law]
= ( 3 + 1 ) + ( -i -2i ) [associative law]
= 4 + (-3i) [consolidated]
= 4 - 3i [consolidated]

You could do the same by using component notation for the complex numbers, avoiding the "i":

(3 - i ) + (1 - 2i )
= (3; -1) + (1; -2) [component notation (real; imaginary)]
= (4; -3) [addition by components]
= 4 - 3i [i-notation]

Mar 19, 2014 | Office Equipment & Supplies

1 Answer

Sigma notation on fx9750gii

The syntax is
Sigma ( function (n),index n, starting value of index n, ending value of index n, increment of n).
If you omit the increment of the index the calculator will assume it is equal to 1

Dec 02, 2012 | Casio FX9750GII Graphic Calculator

1 Answer

Use of numbers on base of sigma lens

If you're referring to the numbers on the aperture ring, you don't use them. Simply turn the ring to its smallest aperture (largest number) and leave it there. Just use the lens the same way you use any other lens without such a ring.
The aperture ring is there for use with older cameras that don't control the aperture from the camera.

Jan 21, 2012 | Sigma Cameras

1 Answer

My TI 84 won't convert my imaginary numbers to fractions. I typed in 1/(1+i) and it won't convert the answer to fraction form. It keeps saying Error Data Type

The TI-84 works with real fractions. It will not convert complex numbers to fractions.

You can convert the real and imaginary components to fractions separately. For your example, 1/(1+i) is .5-.5i. Converting .5 and -.5 to fractions, you get 1/2 + (1/2)i.

Sep 15, 2011 | Texas Instruments TI-84 Plus Calculator

2 Answers

Bibbliography of real numbers

Real Numbers are just numbers like: 1 12.38 -0.8625 3/4 ?2 1998 In fact:

Nearly any number you can think of is a Real Number
Real Numbers include: yes.gif Whole Numbers (like 1,2,3,4, etc) yes.gif Rational Numbers (like 3/4, 0.125, 0.333..., 1.1, etc ) yes.gif Irrational Numbers (like ?, ?3, etc )

Real Numbers can also be positive, negative or zero.
So ... what is NOT a Real Number? no.gif ?-1 (the square root of minus 1) is not a Real Number, it is an Imaginary Number no.gif Infinity is not a Real Number And there are also some special numbers that mathematicians play with that are not Real Numbers
Why are they called "Real" Numbers?

Because they are not Imaginary Numbers.
The Real Numbers did not have a name before Imaginary Numbers were thought of. They got called "Real" because they were not Imaginary. That is the actual answer!
The Real Number Line The Real Number Line is like an actual geometric line.
A point is chosen on the line to be the "origin", points to the right will be positive, and points to the left will be negative.

real-number-line.gif A distance is chosen to be "1", and the whole numbers can then be marked off: {1,2,3,...), and also in the negative direction: {-1,-2,-3, ...}
Any point on the line is a Real Number:

  • The numbers could be rational (like 20/9)
  • or irrational (like ?)
But you won't find Infinity, or an Imaginary Number.
Real does not mean they are in the real world blue-speech.gif They are not called "Real" because they show the value of something real.
In mathematics we like our numbers pure, if we write 0.5 we mean exactly half, but in the real world half may not be exact (try cutting an apple exactly in half).

Jul 10, 2011 | Computers & Internet

1 Answer

I want to remove the word fix from the top of the calculator

You've got the display set to fixed decimal notation. To change it, press SHIFT MODE 7 to switch to a scientific notation or SHIFT MODE 8 and then 1 or 2 to switch to one of the norm display modes.

norm1 switches to scientific notation if the magnitude of the number is less than 0.01 .
norm2 switches to scientific notation if the magnitude of the number is less than 0.000000001 .

Jun 07, 2011 | Casio FX991ES Scientific Calculator

1 Answer

I have a TI30XA calculator and want to know how to multiply numbers using scientific notation. I have learned how to enter a number (e.g., 1.5 x 10 -6), but when I try to multiply it by something (e.g.,...

Press 2nd [SCI] to switch the calculator to display all results in scientific notation. The results are the same whether you do it in scientific notation or not, it's just how the number is displayed.

Feb 13, 2011 | Texas Instruments TI-30XA Calculator

1 Answer

I am trying to solve imaginary number equations with matrix using the TI-84 For example: (8+15i)x-8y = 10 -8x-(8-10i)y = 0 8+15i -8 10 -8 8-10i 0 should i convert to another form?

I am afraid you cannot use the TI8xPlus family of calculators to solve linear systems in matrix form. In this calculator, matrices must have real coefficients.
You can however separate (expand) the problem into a linear system of 4 equations in 4 unknowns and try to solve it with the calculator.
  1. define X = a+i*b
  2. Define Y=c+i*d
  3. Rewrite the first equation substituting a+i*b for X and c+i*d for y.
  4. Gather all real terms together, and all imaginary terms together on the left.
  5. You will have (8a-15b-8c) +i(15a+8b-8d) = 10 +0i
  6. This equation can be split into two equations by saying that
  • the real part pf the left member is equal to the real part of the right member, this gives 8a-15b-8c=10, and
  • the imaginary part of the left member is equal to the imaginary part of the right member, this gives 15a+8b-8d=0
Similarly, you rewrite the second complex equation substituting a+ib for X and c+id for Y, then expand the binomial products, gather the real parts on the left together, and the imaginary parts on the left together. After that you equate the real part on the left to the real part on the right, and do the same for the imaginary parts.

If I did not make mistakes during the expansions and the gathering of terms you should get the following equation
-(8a+8c+10d) +i*(-8b+10c-8d) =0+i*0 from which you extract an equation for the real parts, -(8a+8c+10d)=0 and another for the imaginagy parts i*(-8b+10c-8d) =i*0

If I did not make mistakes (you should be able to find them, if any) your system of two linear equations with complex coefficents has been converted to a system of 4 linear equations with real coefficients.

-8b+10c-8d =0

Now, you can in theory solve this system with help of the calculator, to find a, b, c, and d. When these are found, you can reconstruct the X and Y solutions.

Now get to work: Ascertain that my extracted equations are correct, then solve for a, b,c, and d, and reconstruct X and Y.
I am no seer, but my hunch is that this system is degenarate. I will not explain what that means.

Feb 10, 2010 | Texas Instruments TI-84 Plus Calculator

2 Answers

Mean (x-bar), variance (s^2) and standard deviation (s)

Enter 1 then press the (SIGMA)+ button (SIGMA) looks like a sideways capital M ....its a Greek letter.

Then enter 2 and press the (SIGMA)+ button
Then enter the next value and press the (SIGMA)+ button

After you press the (SIGMA)+ button the calculator displays the number of numbers you have entered

Once all numbers of your sample have been entered press 2nd and the button corresponding to x-bar

sample st. dev is the (sigma)n-1 button (need to use 2nd button)
variance is (std. dev.)^2

population st. dev is the (sigma)n-1 button (need to use 2nd button)
variance is (std. dev.)^2

Jan 18, 2008 | Texas Instruments TI-30XA Calculator

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