TITLE: how to substitute a variable by a number in wolframalpha
QUESTION [5 upvotes]: Peace be upon you,
How can I compute
\begin{align*}
sin'(0)
\end{align*}
in Wolframalpha? like what in Maple, I try
subs(diff(sin(x),x),x=0)

But it doesn't work. I searched the web for "substitution in wolframalpha", but no helpful answer I got.

REPLY [5 votes]: The following all work:

ReplaceAll[Diff[Sin[x], x] , {x -> 0}]
D[Sin[x], x] /. {x -> 0}
Diff[Sin[x], x] where x = 0
Sin'(0)