[6.7] Complex Derivatives - Texas Instruments TI-89 Tip List

which returns {1.3483146067416,0}
This data can be used to test the routine for a fit through an arbitrary point:
xl = {100,200,300,400,500}
yl = {140,230,310,400,480}
h = 300
k = 310
which returns {0.85, 55}
This function can be used to find the unadjusted correlation coefficient for the curve fits:
corrhk(f1,xl,yl)
func
©(f1,xlist,ylist)return r^2 for y=f1(x)
©15mar00/dburkett@infinet.com
1-sum((seq(f1|x=xl[k],k,1,dim(xl))-yl)^2)/sum((seq(yl[k],k,1,dim(xl))-mean(yl))^
2)
Endfunc
For example, if the correlation equation coefficients are {b,a} as returned by linreghk(), use
corrhk(polyeval({b,a},x),xlist,ylist)
where xlist and ylist are the lists of data point coordinates.

[6.7] Complex derivatives

The 89/92+ can find derivatives of functions in complex variables as well as those in real variables.
Make sure that you specify that the variables are complex using the underscore character "_".
For example
(1/(1-z_),z_)
returns
1
(z_−1) 2
To put the result in terms of the real and imaginary components, use
(f(z_),z_)|z_=a+bi
where 'i' is the complex unit operator. So,
(1/z_,z_)|z_=a+bi
returns
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