How do i find inverses numbers on my calculator

SOURCE: in this calculator how to calculate log inverse of

My way is really slow b/c I don't know the right way, but I always clear my memory (SHIFT, CLR on the 9 button), then type it in as an equation, for example: log(X)=-15.3, then press SHIFT, and SOLVE (on the calc button), then press =. It freezes up the calculator for several seconds though =/

SOURCE: ERR:SINGULAR MAT when finding inverse of matrices

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

SOURCE: calculate inverse module

Hello,
The TI 89 cannot calculate the inverse modulo, but you can enter a program that can do that. I found a link to such program. Here it is.

http://www.cartesionline.it/materiali/algebra_numb_theory.cfm

Hope it helps.

SOURCE: Error when using inverse trig inever used to get

If you are trying to calculate arcsine (sin^-1) and arccosine (cos^-1) the only whole number you can use are -1,0 and 1. This due to the fact that the domain of these functions is the closed interval [-1,1]. Any value outside that interval will trigger an error message. No limitation on the argument of the arc tangent or arc cotangent functions

If the angle unit is set to degree the arc will be in degrees, and if angle unit is radian, the arc will be in radians.