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Where students study out loud.

Ask anything — privately to your teacher, inside your cohort, or open to the whole school. Tips and resources welcome too.

QuestionMy cohort· IB Math AA HL

Chain rule on (x²+1)^5 — keep getting 5(x²+1)⁴ and stuck there

When I apply the chain rule on f(x) = (x² + 1)⁵, I get 5(x²+1)⁴ and stop. What's the part I'm missing about the inner derivative? My answer key has 10x(x²+1)⁴ but I can't see where the 10x comes from.

?Anonymous·143d ago·4 replies#chain-rule#derivatives

QuestionTeacher onlySolved· AP Physics C: Mech.

Rolling without slipping — energy method giving wrong answer

I'm using ½mv² + ½Iω² but my final answer is half the expected value. Suspect I'm double-counting the moment of inertia. Could you check my working in the attached image?

LMinseo Lee·144d ago·1 reply#rotation#energy

QuestionMy cohort· AP Calculus BC

Integration by parts — when does it actually help?

I keep trying IBP and ending up with a worse integral. Is there a quick way to know when it's the right tool before I commit?

?Anonymous·144d ago·3 replies#integration#by-parts

QuestionTeacher only· IB Biology HL

IA topic — is enzyme kinetics too risky?

Considering Lineweaver-Burk plot for my IA but worried about access to a spectrophotometer reliable enough. Should I pivot?

PJiwoo Park·144d ago·1 reply#ia#enzymes

QuestionMy cohortSolved· IGCSE Chemistry

Why do moles ratio give different masses?

If 2 moles of H₂ react with 1 mole of O₂ to make 2 moles of H₂O — the mass on left is 4g + 32g = 36g but H₂O is 36g too. So masses match… but ratios don't? Confused.

?Anonymous·144d ago·5 replies#moles#stoichiometry

TipOpen to school· IB Math AA HL

How I went from 5 → 7 on Paper 1 in 6 weeks

Sharing my weekly schedule + the 3 problem types I drilled. TL;DR: don't grind random sets, group by misconception.

KEunbi Kang·144d ago·11 replies#paper-1#study-plan

ResourceOpen to school· AP Biology

Cellular respiration mind-map (PDF)

Compiled this for my own review and figured someone else might use it. Covers glycolysis → ETC with all the regulation points.

CDaehyun Choi·145d ago·6 replies#respiration#mind-map#pdf

QuestionMy cohort· IGCSE Physics

Refraction question with two lenses — confused about virtual image position

When the object is between F and 2F of the first lens, the image forms past the focal point of the second lens. How do I figure out if the final image is real or virtual without drawing the whole ray diagram?

CDaehyun Choi·146d ago·2 replies#optics#lenses

TipMy cohort· A Level Math

Pure vs Further Math — when Further is worth the extra paper

Took both in year 12. Further pays off only if you're applying STEM at Oxbridge / Imperial — otherwise the time is better spent on Physics. Sharing my decision matrix.

PJiwoo Park·146d ago·4 replies#further-math#course-selection

QuestionOpen to school· Study skills

How do you balance IB + university apps in senior year?

Genuinely struggling to fit Common App essays into the IA grind. Anyone done this and lived to tell the tale?

YHyunsoo Yoon·147d ago·14 replies#uni-apps#time-management

TipOpen to school· Study skills

Pomodoro doesn't work for me — here's what does

25/5 always broke my flow on long math problems. Switched to 90/15 and my output doubled. Sharing in case anyone else has this issue.

LMinseo Lee·148d ago·9 replies#focus#habits

ResourceOpen to school· IB Math AA HL

Past paper index — sorted by misconception

Spent the weekend going through 20 past papers and grouping the questions by what specific misconception they catch. Sharing the spreadsheet.

KEunbi Kang·149d ago·17 replies#past-papers#spreadsheet