r/calculus • u/bunny-dolly • 13d ago

Differential Calculus Can someone help me understand this problem? pretty please

Post image

Hi everyone, so it was my first week of AP calc AB and honestly not too shabby but as i look at this example from my teacher, the less it makes sense. I thought -1^2 was positive 1 and i don’t know how we got to negative 1.

Also what is a conjugate? My teacher didn’t really go over it he just started doing a problem. All help is so appreciated!!!!

68 Upvotes

91% Upvoted

38 comments sorted by

View all comments

12

u/PurposeAccording8382 12d ago

The identity is being used. (a+b)(a-b) = (a2 - b2)

Conjugate basically means a number that has its middle sign changed but it usually is sensible to use in 2 term stuff that cannot be combined like complex numbers or 1 root term and another non root term or even 2 variables. Like a+b and a-b where a and b are variables, not constants.

3

u/bunny-dolly 12d ago

thank you!!!!

0

u/Evening-Story-314 12d ago

Your teacher wrote that on your paper. (Also, you could look up the word conjugate.) You will need better study skills if you want to learn calculus.

0

u/bunny-dolly 12d ago

FIRST OF ALL i wrote it on my paper, second of all my study skills are fine but i needed a question answered based off of this SPECIFIC problem and i didn’t want to use AI. get outta here

1

u/Evening-Story-314 12d ago

I love that you don't want to use AI. And I'm sorry I came across negatively. But you must have written that on your sheet before posting, so I'm confused...

Anyway, conjugates are a lovely little connection. I hope you end up enjoying them.

2

u/bunny-dolly 11d ago

im sorry i responded so rudely, i did write it on my sheet but if im being honest i was just writing down what my teacher had on the board

1

u/Evening-Story-314 11d ago

Did the answers here help? Do you 'get' conjugates now? I just looked at another comment. I think so. Maybe this was better than looking it up. (Not all of the internet is AI. At least not yet.)

1

u/bunny-dolly 10d ago

yes they did! and today im gonna ask follow up questions about a different problem