Texas Instruments voyage 200 User Manual - Page 850

The example Program Editor function to the right uses getType() and part() to partially implement symbolic differentiation. Studying and completing this function can help teach you how to differentiate manually. You could even include functions that the cannot differentiate, such as Bessel functions. :d(y,x) :Func :Local f :If getType(y)="VAR" : Return when(y=x,1,0,0) :If part(y)=0 : Return 0 ¦ y=p,ˆ,i,numbers :part(y,0)! f :If f="L" ¦ if negate : Return ë d(part(y,1),x) :If f="−" ¦ if minus : Return d(part(y,1),x) ì d(part(y,2),x) :If f="+" : Return d(part(y,1),x) +d(part(y,2),x) :If f="ù " : Return part(y,1)ù d(part(y,2),x) +part(y,2)ù d(part(y,1),x) :If f="{" : Return seq(d(part(y,k),x), k,1,part(y)) :Return undef :EndFunc PassErr CATALOG PassErr See ClrErr program listing example. Passes an error to the next level. If "errornum" is zero, PassErr does not do anything. The Else clause in the program should use ClrErr or PassErr. If the error is to be processed or ignored, use ClrErr. If what to do with the error is not known, use PassErr to send it to the next error handler. (See also ClrErr.) Pause CATALOG Pause [expression] Program segment: Suspends program execution. If you include expression, displays expression on the Program I/O screen. expression can include conversion operations such as 4DD and 4Rect. You can also use the 4 operator to perform unit and number base conversions. If the result of expression is too big to fit on a single screen, you can use the cursor pad to scroll the display. Program execution resumes when you press ¸. © :ClrIO :DelVar temp :1"temp[1] :1"temp[2] :Disp temp[2] :¦ Guess the Pattern :For i,3,20 : temp[iì2]+temp[iì1]"temp[i] : Disp temp[i] : Disp temp,"Can you guess the next","number?" : Pause :EndFor © 852 Appendix A: Functions and Instructions