Evaluating the derivative at a point

[DifEqRules]

After I store a function, say y(x) = sin(x), how do I find the derivative and evaluate it at a point? In other words, what is the TI-89 syntax that calculates y'(0)?

Phil Moore

[BlainUSM]

Here are a few approaches:

Approach 1:

d(sin(x), x)|x=0

Approach 2:

sin(x)->y(x)

d(y(x),x) -> yp(x)

yp(0) = 1

The vertical bar "|" can be used in other expressions, as well. For example, to evaluate sqrt(a^2 + b^2) with a = 3 and b = 4 we may enter the following:

sqrt(a^2 + b^2)| a = 3 and b = 4

Our output should be 5.