## Archive for June, 2015

### Trigonalisation on the TI89 step by step

Saturday, June 27th, 2015

Trigonalisation can be done step by step on the TI89 using the LInear Algebra Made Easy at http://www.ti89.com/?a=LAME

For further information and examples:
https://fr.wikipedia.org/wiki/Trigonalisation#Exemples_de_trigonalisation

### Solve Cauchy Euler Differential Equation Step by Step on the TI89

Saturday, June 27th, 2015

2. Order Cauchy Euler Differential Equations are of the format

x^2*y” + b*x*y’ + c*y=f(x)

Homogeneous solutions are linear combinations of format c1*x^m1 + c2*x^m2 where m1 and m2 are zeros of a corresponding char. equation.

Good news for TI89 users:
This type of Differential Equation can now be solved step by step using Differential Equation Made Easy at http://www.ti89.com/?a=DEQME

### Cayley Hamilton procedure on the TI89 step by step

Friday, June 26th, 2015

The Cayley Hamilton is a nifty procedure to find the inverse of a matrix using
the characteristic polynomial of a given square matrix. So no Row Echolon or similar is needed.

We just included this Cayley Hamilton in the Linear Algebra Made Easy TI89. Best of all complete steps are shown until the inverse matrix is found.

http://math.stackexchange.com/questions/780160/inverse-of-this-3-by-3-matrix-using-the-cayley-hamilton-theorem

### TI89.com for mobile devices

Wednesday, June 24th, 2015

TI89.com is now mobile responsive: once you access www.TI89.com using a cell phone or tablet you will access the mobile TI89.com site.

Note: the giveaway puzzle must be accessed on the full (not the mobile) site.

### New Giveaway Puzzle at www.ti89.com

Wednesday, June 24th, 2015

Find a new Giveaway Puzzle at the top of www.TI89.com.
The first person to solve this one qualifies for a free TI89 app.

The solutions to the previous were clever and winners are now happy users of our TI89 apps.

### User comment (M.B.): Just want to thank you for the fabulous programs for Statistics

Friday, June 12th, 2015

Stats made easy made my stats class a breeze. I got all answers correct thanks to the stats program. I love the program and will try to impress on others that the money is worth every penny when you can get an A in the class. I got a 93% in my Stats class. Thank You so much again. Now I am going to purchase three more programs, Microeconomics, Financial and Accounting, and Portfolio, this summer, next month for my major classes. I will buy them early and learn how to use them over the summer then I will be ready for next semester just as I did with the Stats program. I worked all winter term to learn how to work the program and aced the class. This is the only draw back to the programs is not precise user guides to show you how to use the programs, you have to figure that out yourself [TI89.com comment: “Please check the user video at
https://youtu.be/saVZesFUVqY . More will be added if needed.”] . But, once you have figured out the process, you are on your way. Keep up the great work. I am so, so glad that your programs came my way by me asking the right question on google!!!!

Satisfied Purchaser of Stats made easy
Sent from Windows Mail

### Watch John do his Calculus Homework Step by Step on the TI89

Friday, June 12th, 2015

Watch John do his Calculus Homework Step by Step on the TI89:

He does Limits, Derivatives, Integrals and Differential Equations in a few minutes , Step by Step

### WEEKLY GIVEAWAY PUZZLE (6-11-15):

Thursday, June 11th, 2015

Arrange the digits 1,2,3,4,5,6,7,8,9 in order from left to right,  insert + and – as desired to get 79  ?