My ti 84 doesn't work properly. I turned it on and this and inverse comes on. All the buttons don't work, I can't even turn it off . It goes off by itself after awhile. Tried the take out batteries and hold ON button for 10 secs but it doesn't work for me please helpppp I don't want to buy a new one

2nd will activate the second function on a key.

To get the inverse trigonometric functions press the 2nd key then the trig function key. If you'll look at the key legends above the SIN, COS, and TAN keys you'll see the standard math notations for their inverse function.

Hi
if you can turn on and then click on the on button and this is the only ket that works then its an hardware problem and it can be fixed
let me know if you want to fix

[email protected]

Jack

there is a button on which x(-1) is written,this button is found to the left of the "sin" button.this acts as inverse. for e.g- if you want the inverse of 5, press 5 and then click on that button.

Hi Robert9004x2,

If you want to examine the matrix you want to inverse and, the one that is given you trouble pressing [2nd] [MATRX]. Then stroll and, select the one you want to look at by pressing, [ENTER]. You'll have to press, [ENTER] again and, matrix should display at the Home screen. At the Home when you get to them your looking for the ones that are not square, like 2 by2 or 4 by 4 etc. You might need to re-edit this matrix so, that it is square.

Your trying to invert a matrix that isn't square you might be using using the proper key sequence to create a inverse matrix. Here what the correct inverse matrix look on the Ti 84 Plus Home screen.

And pictured below is a Matrix is being inverted by using the ^ and the -1 keys. Which to inverse a Matrix on the Ti 84 Plus you have to use the [x^-1] key.

This is not the proper way to inverse a Matrix on the Ti 84 Plus. The proper way to inverse of a matrix, the [x-1] key must be used, instead of pressing the sequence [^][-][1]. The [x-1] key is the official inverse key and is located right under the Math key. It is also the same key that you use to get to the matrix menus. The [^][-][1] sequence is only raising the matrix to the -1 power and, will cause an error too. If you need any more help, just post a comment and, I'll respond quickly.

The x^-1 key is in the leftmost column of the keyboard, below the MATH key.

If you want the inverse trig functions, press 2ND then the trig function key.

A singular matrix has no inverse. It's the equivalent of zero: trying to take the inverse of zero is an error. Check the matrix to make sure you have entered it correctly. If the error persists, could you post the matrix in question?

Having received no response in over a month, I assume this is no longer a problem.

If a matrix has a determinant of 0, this error appears. If you get this error, your matrix doesn't have an inverse.

The problem is simple. You're trying to get an [H+] concentration which is obviously going to have a value of some number times ten raised to a negative power. Therefore, you have to insert the negative value of the pH into the 10^(x). When you insert said negative number you will come out with the right answer.
i.e.
The pH of a sample of human blood was calculated to be 7.41. What is the [H+] concentration of the blood?
10^(-7.41) = [H+]
[H+] = 3.9 E-8  
(the answer should only have two sig. figs because the pH has two digits after the decimal.