TITLE: Matrix exponential weirdness in WolframAlpha - it fails on diagonal matrices?
QUESTION [5 upvotes]: So Wikipedia says this, which makes sense:

But Wolfram computed this:

Is this a bug or am I just extremely tired?

REPLY [11 votes]: For the matrix exponential, use MatrixExp instead of Exp. Wolfram Alpha interprets Exp to be the entrywise exponentiation.