MHB 4.1.306 AP Calculus Exam Area under Curve

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The discussion centers on calculating the area of the region in the first quadrant bounded by the curve y=e^(x/2) and the line x=2. The integration of e^(x/2) yields the expression 2e^(x/2), evaluated from 0 to 2, resulting in the area being 2e-2. A suggestion is made to include a constant C in the indefinite integral, which is acknowledged. Additionally, there is an attempt to graph the area using TikZ, but issues arise with displaying the vertical line and shading the region.
karush
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$\textsf{What is the area of the region in the first quadrant bounded by the graph of}$
$$y=e^{x/2} \textit{ and the line } x=2$$
a. 2e-2 b. 2e c. $\dfrac{e}{2}-1$ d. $\dfrac{e-1}{2}$ e. e-1Integrate
$\displaystyle \int e^{x/2}=2e^{x/2}$
take the limits
$2e^{x/2}\Biggr|_0^2=2e-2$which is a.any suggestions ?
 
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karush said:
$\textsf{What is the area of the region in the first quadrant bounded by the graph of}$
$$y=e^{x/2} \textit{ and the line } x=2$$
a. 2e-2 b. 2e c. $\dfrac{e}{2}-1$ d. $\dfrac{e-1}{2}$ e. e-1Integrate
$\displaystyle \int e^{x/2}=2e^{x/2}$
take the limits
$2e^{x/2}\Biggr|_0^2=2e-2$which is a.any suggestions ?

Put a +C at the end of your indefinite integral, and then you are correct.
 
karush said:
Integrate
[math]\int e^{x/2}[/math] dx [math]=2e^{x/2}[/math] + C
Tsk tsk.

-Dan
 
\begin{tikzpicture}
%preamble \usepackage{pgfplots}
\begin{axis}[axis lines=middle, grid=both]
\addplot[
draw = red,
domain=-.5:3,
range=-2:8,
samples=50
] {exp(e^(x/2)};
\draw[solid] (2,0)- -(2,6);
\end{axis}
\end{tikzpicture}ok I tried to tikx $e^{x/2}$ and $x=2$ but kinda ! don't see any vertical line
also be nice for a light shade in the region
 
karush said:
\begin{tikzpicture}
%preamble \usepackage{pgfplots}
\begin{axis}[axis lines=middle, grid=both]
\addplot[
draw = red,
domain=-.5:3,
range=-2:8,
samples=50
] {exp(e^(x/2)};
\draw[solid] (2,0)- -(2,6);
\end{axis}
\end{tikzpicture}ok I tried to tikx $e^{x/2}$ and $x=2$ but kinda ! don't see any vertical line
also be nice for a light shade in the region

Wait, what? Are you trying to graph the area?
 
There are probably loads of proofs of this online, but I do not want to cheat. Here is my attempt: Convexity says that $$f(\lambda a + (1-\lambda)b) \leq \lambda f(a) + (1-\lambda) f(b)$$ $$f(b + \lambda(a-b)) \leq f(b) + \lambda (f(a) - f(b))$$ We know from the intermediate value theorem that there exists a ##c \in (b,a)## such that $$\frac{f(a) - f(b)}{a-b} = f'(c).$$ Hence $$f(b + \lambda(a-b)) \leq f(b) + \lambda (a - b) f'(c))$$ $$\frac{f(b + \lambda(a-b)) - f(b)}{\lambda(a-b)}...

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