fixed in C and JS, Python has already been fixed

I streamlined the test suite

your function is correct, except the two branches of your ternary, they're the wrong way around

a boolean would have been a better choice, but there are 7 translations now, it's too late :(

this is a duplicate of this issue

Similar problem in JS

Approved by someone.

Python. Also my solution passed with this issue still being prevalent.

Which language did you try?

Incorrect answer for eq='-66x^13+90x^12-57x^11+0x^10':

'-858x^12+1080x^11-627x^10' should equal '-858x^12+1080x^11-627x^10+0x^9'

Why would I include a term where the coefficient is 0? Surely that term is completely unnecessary and I can just ignore it when finding the derivative?

Lua translation

Forked & Approved. Honor points to CrSb0001

Sorry, but this is not a valid issue, it's an 8kyu kata, it's suppossed to be easy. Besides it's easy in every language.

it's so easy if you used python language, you should delete python in this question

Ha ha, good kata. It might seem more than an 8 for a total beginner though...