I'm using the UESPWiki for all my information on this.

The Adept level frenzy spell for Illusion is Frenzy, which states: Creatures and people up to level 14 will attack anyone nearby for 60 seconds

Then if you start looking at perks, the Dual Casting perk states:
Dual casting an Illusion spell overcharges the effects into an even more powerful version. This slightly more than doubles the maximum level of any level-based Illusion spell. Level adjustments from Animage or Kindred Mage or Hypnotic Gaze or Aspect of Terror or Rage are applied before the doubling effect (220% spell power for 280% magicka cost).

And the above mentioned Rage perk is as follows: Frenzy spells work on higher level opponents (+12 levels to spell maximum). Cumulative with Kindred Mage and Animage.

So, if I have my math right, the way these perks would stack is as follows:

Frenzy (level 14)
+Rage (+12)
= 26
+Dual Casting (x2)
=52

So a dual cast Frenzy spell, with the Rage perk, would effect NPC's up to level 52.

Is my math correct on this?

I want to make sure, because I'm looking to build a character around Frenzy.

It's technically 2.2x
Its more like 60 ish.

Kindred adds 10 to NPC's

Add a few more if you're a vampire.

Yea I'm looking to avoid the Kindred Mage perk, if anything so I can use those perks towards others that I'd rather have.

I figure if I can still Frenzy people up to level 52, I'll be pretty good. Even better if it's as you said, closer to 60ish.