Form calculus takes where triangle replotted? (8)

I believe the answer is:

integral

I'm a little stuck... Click here to teach me more about this clue!

'form calculus' is the definition.
'integral' can be an answer for 'calculus' (integral calculus is a kind of calculus). I'm not sure about the 'form' bit.

'where triangle replotted?' is the wordplay.
'triangle' can be anagrammed to 'INTEGRAL'.
Though, I am not sure how this is indicated.

'takes' is the link.

Can you help me to learn more?

(Other definitions for integral that I've seen before include "Belonging as an essential part" , "'Inherent, inbuilt (8)'" , "Basic" , "Mathematical quantity" , "Unimpaired" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.