Let me start by saying that I have a TI-89 Titanium, so perhaps what I list as errata is not for the TI-89, which differs from the Titanium. Regardless, I am working through Carl Swenson's book* Getting Started with the TI-89 Graphing Calculator,* quite a good book, but errors pop up now and then. Those that trouble me most follow.

**Chapter 13, page 56** has two sum equations that are incorrect. I found the correct forms at TechniCalc. Change the equations to:

The commands in Figure 13.3 will now work.

**Chapter 16, page 68** has code for a program called* rsum()* that will not work as written. To make it work, omit the final 1 in each summation command; that is, not

but

Fix all three instances and it will work.

**Chapter 19, page 83** has no error but the equation is missing. It is simple enough, but here it is anyway:

**Chapter 21, page 92** needs a second closing parens added to the piecewise equation for y1.

**Chapter 24, page 104** has a boxed-in* Tip* for unlocking the data file. The last value should be 22, not 21.

**Chapter 26, page 112** lacks the full equation for the* overdamped case.* The equation to enter is:

deSolve(y''+3*y'+2*y=0 and y(0)=-.5 and y'(0)=3,t,y)

**Chapter 26, page 113** lacks the equation for the Home menu's F2:zeros() command. You can cut and paste from the equation in the history above the entry field then delete the "y=" part, but here it is:

zeros(2.**e*^(-t)-2.5**e*^(-2*t),t)

**Chapter 26, page 114** lacks two equations that are not difficult to figure out; nevertheless, here they are:

deSolve(y''+2*y'+2*y=0 and y(0)=-.5 and y'(0)=3,t,y)

zeros((2.5*sin(t)-.5*cos(t))**e*^(-t),t)