HP 49g manual Functions Deriv and Dervx

where the limit is to be calculated. Function lim is available through the command catalog (‚N~„l) or through option 2. LIMITS & SERIES… of the CALC menu (see above).

Function lim is entered in ALG mode as lim(f(x),x=a) to calculate the limit lim f (x) . In RPN mode, enter the function first, then the expression

x→a

‘x=a’, and finally function lim. Examples in ALG mode are shown next, including some limits to infinity, and one-sided limits. To calculate one-sided limits add +0 or -0 to value to the right of the arrow. A “+0” means limit from the right, while a “-0” means limit from the left. The infinity symbol is associated with the 0 key, i.e.., „è.

Functions DERIV and DERVX

The function DERIV is used to take derivatives in terms of any independent variable, while the function DERVX takes derivatives with respect to the CAS default variable VX (typically ‘X’). While function DERVX is available directly in the CALC menu, both functions are available in the DERIV.&INTEG sub- menu within the CALCL menu ( „Ö).

Function DERIV requires a function, say f(t), and an independent variable, say, t, while function DERVX requires only a function of VX. Examples are shown next in ALG mode. Recall that in RPN mode the arguments must be entered before the function is applied.

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