Asklemmy

43945 readers

642 users here now

A loosely moderated place to ask open-ended questions

Search asklemmy 🔍

If your post meets the following criteria, it's welcome here!

Open-ended question
Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
Not ad nauseam inducing: please make sure it is a question that would be new to most members
An actual topic of discussion

Looking for support?

Looking for a community?

Lemmyverse: community search
sub.rehab: maps old subreddits to fediverse options, marks official as such
!lemmy411@lemmy.ca: a community for finding communities

~Icon~ ~by~ ~@Double_A@discuss.tchncs.de~

founded 5 years ago

MODERATORS

122

Mitochondria is the power house of the cell (lemm.ee)

submitted 3 months ago* (last edited 3 months ago) by red_pigeon@lemm.ee to c/asklemmy@lemmy.ml

125 comments fedilink hide all child comments

This (arguably unhelpful) phrase seems to be taught across schools all over the world. What are some other phrases like this that are common ?

you are viewing a single comment's thread
view the rest of the comments

[–] olafurp@lemmy.world 3 points 3 months ago (1 children)

ax^2 + bx + c = 0
ax^2 + bx = -c move the c over
x^2 + (b/a)x = -c/a divide by a
x^2 + (b/a)x +(b/2a)^2 = -c/a + (b/2a)^2 complete the square
(x + b/2a)^2 = -c/a + (b/2a)^2 factor the left hand side
x + b/2a = sqrt(-c/a + (b/2a)^2) now we just tidy it up
x = -b/2a + sqrt(-c/a + b^2/4a^2)
x = -b/2a + (2a/2a) sqrt(-c/a + b^2/4a^2)
x = (-b + (2a)sqrt(-c/a + b^2/4a^2))/2a
x = (-b + sqrt(-4ac + b^2))/2a move 2a into the square root and multiply it with what's inside

The derivation of the quadratic formula is nice because it doesn't rely on anything fancy and it's all tricks the teacher is likely to teach around the same time you're learning it. It's not voodoo shit, it's just the ax^2 + bx + c = 0 and you solve for x.

[–] JWBananas@lemmy.world 1 points 3 months ago

Thanks for the alternative explanation. Completing the square never made much sense to me either, so I never would have arrived there.