Dave wrote:

. . .The SWR depends on the magnitude of
the impedances not the angle, so you could have a minimum SWR with a big
reactance and small real component.

That's not true. For example, impedances of 50 + j0, 35.36 + j35.36, and
0 + j50 ohms all have the same magnitude (50 ohms), but a 50 ohm cable
connected to loads of those impedances will have SWRs of 1, 2.41, and
infinity respectively.

Correct formulas for calculating SWR can be found in the ARRL Antenna
Book, the ARRL Handbook, or any respectable transmission line text.
Incorrect ones can, I'm sure, be found on the Web and elsewhere.

Roy Lewallen, W7EL