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Author: Tinku Tara

lim-n-1-1-2-1-3-1-4-1-n-ln-n-

Question Number 224852 by fantastic last updated on 07/Oct/25 $$\underset{{n}\rightarrow\infty} {\mathrm{lim}}\:\frac{\mathrm{1}+\frac{\mathrm{1}}{\mathrm{2}}+\frac{\mathrm{1}}{\mathrm{3}}+\frac{\mathrm{1}}{\mathrm{4}}+…+\frac{\mathrm{1}}{{n}}}{{ln}\left({n}\right)}=? \\ $$ Answered by vnm last updated on 08/Oct/25 $$\mathrm{lim}=\mathrm{1} \\ $$$$\mathrm{This}\:\mathrm{follows}\:\mathrm{from}\:\mathrm{the}\:\mathrm{double}\:\mathrm{inequality}\: \\ $$$$\mathrm{which}\:\mathrm{is}\:\mathrm{evident}\:\mathrm{if}\:\mathrm{we}\:\mathrm{plot}\:…

a-piece-of-chalk-rests-on-a-horizontal-board-with-0-1-Suddenly-the-board-starts-to-move-horizontally-at-a-speed-of-2m-per-second-and-after-a-time-it-stops-abruptly-find-the-length-of-the-line-d

Question Number 224853 by fantastic last updated on 07/Oct/25 $$ \\ $$$$\mathrm{a}\:\mathrm{piece}\:\mathrm{of}\:\mathrm{chalk}\:\mathrm{rests}\:\mathrm{on}\:\mathrm{a} \\ $$$$\mathrm{horizontal}\:\mathrm{board}\:\mathrm{with}\:\mu=\mathrm{0}.\mathrm{1} \\ $$$$\mathrm{Suddenly}\:\mathrm{the}\:\mathrm{board}\:\mathrm{starts}\:\mathrm{to} \\ $$$$\mathrm{move}\:\mathrm{horizontally}\:\mathrm{at}\:\mathrm{a}\:\mathrm{speed}\:\mathrm{of} \\ $$$$\mathrm{2m}\:\mathrm{per}\:\mathrm{second}\:\mathrm{and}\:\mathrm{after}\:\mathrm{a} \\ $$$$\mathrm{time}\:\tau\:\mathrm{it}\:\mathrm{stops}\:\mathrm{abruptly}.\:\mathrm{find}\: \\ $$$$\mathrm{the}\:\mathrm{length}\:\mathrm{of}\:\mathrm{the}\:\mathrm{line}\:\mathrm{drawn} \\…

sec-d-

Question Number 224833 by fantastic last updated on 06/Oct/25 $$\int\mathrm{sec}\:\theta\:{d}\theta \\ $$ Answered by taha3738 last updated on 06/Oct/25 $$\int\:\mathrm{sec}\:\theta\:{d}\theta\:=\:\int\:\frac{\mathrm{sec}\:\theta\:\left(\mathrm{sec}\:\theta\:+\:\mathrm{tan}\:\theta\right)}{\mathrm{sec}\:\theta\:+\:\mathrm{tan}\:\theta}\:{d}\theta \\ $$$$=\:\int\:\:\frac{\mathrm{sec}^{\mathrm{2}} \theta+\:\mathrm{sec}\:\theta\:\mathrm{tan}\:\theta}{\mathrm{sec}\:\theta\:+\:\mathrm{tan}\:\theta\:}\:{d}\theta\:=\:\mathrm{ln}\:\mid\:\mathrm{sec}\:{x}\:+\:\mathrm{tan}\:{x}\:\mid\:+\:{C} \\ $$$${Because}\:\frac{{d}}{{d}\theta}\:\left(\:\mathrm{sec}\:\theta\:+\:\mathrm{tan}\:\theta\:\right)\:=\:\frac{{d}}{{d}\theta}\:\mathrm{sec}\:\theta\:+\:\frac{{d}}{{d}\theta}\:\mathrm{tan}\:\theta…

Use-the-Gauss-Bonnet-Theorem-to-show-that-the-number-of-holes-in-a-straw-is-1-Then-associate-it-and-show-that-the-Genus-on-the-surface-is-1-

Question Number 224806 by fkwow344 last updated on 05/Oct/25 $$\mathrm{Use}\:\mathrm{the}\:\mathrm{Gauss}\:\mathrm{Bonnet}\:\mathrm{Theorem}\:\mathrm{to}\:\mathrm{show}\:\mathrm{that}\:\mathrm{the} \\ $$$$\mathrm{number}\:\mathrm{of}\:\mathrm{holes}\:\mathrm{in}\:\mathrm{a}\:\mathrm{straw}\:\mathrm{is}\:\mathrm{1}. \\ $$$$\mathrm{Then}\:\mathrm{associate}\:\mathrm{it}\:\mathrm{and}\: \\ $$$$\mathrm{show}\:\mathrm{that}\:\mathrm{the}\:\mathrm{Genus}\:\mathrm{on}\:\mathrm{the}\:\mathrm{surface}\:\mathrm{is}\:\mathrm{1}. \\ $$ Answered by MrAjder last updated on 18/Oct/25…

Question-224807

Question Number 224807 by fantastic last updated on 05/Oct/25 Commented by fantastic last updated on 05/Oct/25 $${It}\:{took}\:{me}\:\mathrm{10}\:{to}\:\mathrm{15}\:{minutes}\:{to}\:{solve} \\ $$$${this}\:{question}.{It}\:{was}\:{not}\:{too}\:{hard} \\ $$$${but}\:{the}\:{question}\:{is}\:{very}\:{interesting} \\ $$$${Here}\:{is}\:{the}\:{question}: \\ $$$${A}\:{bottle}\:{of}\:{syllendrical}\:{shape}…