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diff --git a/Master/texmf-dist/doc/latex/probsoln/implicit.tex b/Master/texmf-dist/doc/latex/probsoln/implicit.tex new file mode 100644 index 00000000000..f6b706871cd --- /dev/null +++ b/Master/texmf-dist/doc/latex/probsoln/implicit.tex @@ -0,0 +1,71 @@ +%% +%% This is file `implicit.tex', +%% generated with the docstrip utility. +%% +%% The original source files were: +%% +%% probsoln.dtx (with options: `implicit.tex,package') +%% Copyright (C) 2006 Nicola Talbot, all rights reserved. +%% If you modify this file, you must change its name first. +%% You are NOT ALLOWED to distribute this file alone. You are NOT +%% ALLOWED to take money for the distribution or use of either this +%% file or a changed version, except for a nominal charge for copying +%% etc. +%% \CharacterTable +%% {Upper-case \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z +%% Lower-case \a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z +%% Digits \0\1\2\3\4\5\6\7\8\9 +%% Exclamation \! Double quote \" Hash (number) \# +%% Dollar \$ Percent \% Ampersand \& +%% Acute accent \' Left paren \( Right paren \) +%% Asterisk \* Plus \+ Comma \, +%% Minus \- Point \. Solidus \/ +%% Colon \: Semicolon \; Less than \< +%% Equals \= Greater than \> Question mark \? +%% Commercial at \@ Left bracket \[ Backslash \\ +%% Right bracket \] Circumflex \^ Underscore \_ +%% Grave accent \` Left brace \{ Vertical bar \| +%% Right brace \} Tilde \~} + +\newproblem{imd:circ}{% +Find the gradient of the unit circle ($x^2 + y^2 = 1$).}{% +Differentiating with respect to $x$ gives: +\begin{eqnarray*} +2x + 2y\frac{dy}{dx} & = & 0\\ +\frac{dy}{dx} & = & \frac{-2x}{2y}\\ + & = & \frac{-x}{\sqrt{1-x^2}}. +\end{eqnarray*}} + +\newproblem{imd:ysq:xcuov2mx}{% +Find $\frac{dy}{dx}$, given +\begin{displaymath} +y^2 = \frac{x^3}{2-x} +\end{displaymath}}{% +Differentiating both sides w.r.t.\ $x$: +\begin{eqnarray*} +2y\frac{dy}{dx} & = & \frac{(2-x)3x^2 - x^3(-1)}{(2-x)^2}\\ + & = & \frac{3x^2(2-x) + x^3}{(2-x)^2}\\ + & = & \frac{6x^2 - 3x^3 + x^3}{(2-x)^2}\\ + & = & \frac{6x^2-2x^3}{(2-x)^2}\\ + & = & 2x^2\frac{3-x}{(2-x)^2} +\end{eqnarray*} +Therefore +\begin{displaymath} +y\frac{dy}{dx} = x^2\frac{3-x}{(2-x)^2} +\end{displaymath}} + +\newproblem{imd:exy:IIxay}{% +Differentiate w.r.t.\ $x$: +\begin{displaymath} +e^{xy} = 2x + y +\end{displaymath}}{% +Differentiating both sides w.r.t.\ $x$: +\begin{eqnarray*} +e^{xy}(1y + x\frac{dy}{dx}) & = & 2 + \frac{dy}{dx}\\ +xe^{xy}\frac{dy}{dx} - \frac{dy}{dx} & = & 2 - ye^{xy} \\ +\frac{dy}{dx}(xe^{xy}-1) & = & 2 - ye^{xy}\\ +\frac{dy}{dx} & = & \frac{2-ye^{xy}}{xe^{xy}-1} +\end{eqnarray*}} +\endinput +%% +%% End of file `implicit.tex'. |