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	<id>https://wiki.math.ucr.edu/index.php?action=history&amp;feed=atom&amp;title=022_Sample_Final_A%2C_Problem_7</id>
	<title>022 Sample Final A, Problem 7 - Revision history</title>
	<link rel="self" type="application/atom+xml" href="https://wiki.math.ucr.edu/index.php?action=history&amp;feed=atom&amp;title=022_Sample_Final_A%2C_Problem_7"/>
	<link rel="alternate" type="text/html" href="https://wiki.math.ucr.edu/index.php?title=022_Sample_Final_A,_Problem_7&amp;action=history"/>
	<updated>2026-04-29T08:31:57Z</updated>
	<subtitle>Revision history for this page on the wiki</subtitle>
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	<entry>
		<id>https://wiki.math.ucr.edu/index.php?title=022_Sample_Final_A,_Problem_7&amp;diff=920&amp;oldid=prev</id>
		<title>MathAdmin at 01:11, 7 June 2015</title>
		<link rel="alternate" type="text/html" href="https://wiki.math.ucr.edu/index.php?title=022_Sample_Final_A,_Problem_7&amp;diff=920&amp;oldid=prev"/>
		<updated>2015-06-07T01:11:41Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left diff-editfont-monospace&quot; data-mw=&quot;interface&quot;&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 01:11, 7 June 2015&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l17&quot; &gt;Line 17:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 17:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;!Solution: &amp;amp;nbsp;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;!Solution: &amp;amp;nbsp;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|-&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|-&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|There isn't much to do here, except identify that &amp;lt;math style=&amp;quot;vertical-align: -0.&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;5px&lt;/del&gt;&amp;quot;&amp;gt;T\,=\,5&amp;lt;/math&amp;gt;, &amp;lt;math style=&amp;quot;vertical-align: -5px&amp;quot;&amp;gt;I(t)\,=\,20+30x&amp;lt;/math&amp;gt; and the rate should be written as &amp;lt;math style=&amp;quot;vertical-align: -1px&amp;quot;&amp;gt;r\,=\,10%\,=\,0.10&amp;lt;/math&amp;gt;.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|There isn't much to do here, except identify that &amp;lt;math style=&amp;quot;vertical-align: -0.&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;2px&lt;/ins&gt;&amp;quot;&amp;gt;T\,=\,5&amp;lt;/math&amp;gt;, &amp;lt;math style=&amp;quot;vertical-align: -5px&amp;quot;&amp;gt;I(t)\,=\,20+30x&amp;lt;/math&amp;gt; and the rate should be written as &amp;lt;math style=&amp;quot;vertical-align: -1px&amp;quot;&amp;gt;r\,=\,10%\,=\,0.10&amp;lt;/math&amp;gt;.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Click to the final answer to see them in the formula!&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Click to the final answer to see them in the formula!&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|}&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|}&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l25&quot; &gt;Line 25:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 25:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|-&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|-&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;::Present value = &amp;lt;math&amp;gt;\int_0 ^T I(t)e^{-rt}\,dt&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;,&lt;/del&gt;\,=\,\int_0 ^5 (20+30x)e^{-0.10t}\,dt.&amp;lt;/math&amp;gt;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;::Present value = &amp;lt;math&amp;gt;\int_0 ^T I(t)e^{-rt}\,dt\,=\,\int_0 ^5 (20+30x)e^{-0.10t}\,dt.&amp;lt;/math&amp;gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|}&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|}&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;[[022_Sample_Final_A|'''&amp;lt;u&amp;gt;Return to Sample Exam&amp;lt;/u&amp;gt;''']]&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;[[022_Sample_Final_A|'''&amp;lt;u&amp;gt;Return to Sample Exam&amp;lt;/u&amp;gt;''']]&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>MathAdmin</name></author>
	</entry>
	<entry>
		<id>https://wiki.math.ucr.edu/index.php?title=022_Sample_Final_A,_Problem_7&amp;diff=900&amp;oldid=prev</id>
		<title>MathAdmin: Created page with &quot;&lt;span class=&quot;exam&quot;&gt;Find the present value of the income stream &lt;math style=&quot;vertical-align: -2px&quot;&gt;Y = 20 + 30x&lt;/math&gt; from now until 5 years from now, given an interest rate &lt;...&quot;</title>
		<link rel="alternate" type="text/html" href="https://wiki.math.ucr.edu/index.php?title=022_Sample_Final_A,_Problem_7&amp;diff=900&amp;oldid=prev"/>
		<updated>2015-06-06T04:36:33Z</updated>

		<summary type="html">&lt;p&gt;Created page with &amp;quot;&amp;lt;span class=&amp;quot;exam&amp;quot;&amp;gt;Find the present value of the income stream &amp;lt;math style=&amp;quot;vertical-align: -2px&amp;quot;&amp;gt;Y = 20 + 30x&amp;lt;/math&amp;gt; from now until 5 years from now, given an interest rate &amp;lt;...&amp;quot;&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;&amp;lt;span class=&amp;quot;exam&amp;quot;&amp;gt;Find the present value of the income stream &amp;lt;math style=&amp;quot;vertical-align: -2px&amp;quot;&amp;gt;Y = 20 + 30x&amp;lt;/math&amp;gt; from now until 5 years from now, given an interest rate &amp;lt;math style=&amp;quot;vertical-align: -1px&amp;quot;&amp;gt;r = 10%.&amp;lt;/math&amp;gt;&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
''(Note: Once you plug in the limits of integration, you are finished; you do not need to simplify our answer beyond that step.)''&lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;mw-collapsible mw-collapsed&amp;quot; style = &amp;quot;text-align:left;&amp;quot;&lt;br /&gt;
!Foundations: &amp;amp;nbsp; &lt;br /&gt;
|-&lt;br /&gt;
|The idea of an income stream is bit more complicated to set up than basic interest problems.  We have two forces adjusting the balance of the account: the ''income stream'', usually represented as &amp;lt;math style=&amp;quot;vertical-align: -5px&amp;quot;&amp;gt;I(t)&amp;lt;/math&amp;gt;, which represents the desired income to be withdrawn from the account, and the interest rate paid to the account.  In order to evaluate this result, we use the formula&lt;br /&gt;
|-&lt;br /&gt;
|&lt;br /&gt;
::present value = &amp;lt;math&amp;gt;\int_0 ^T I(t)e^{-rt}\,dt,&amp;lt;/math&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
|where &amp;lt;math style=&amp;quot;vertical-align: 0px&amp;quot;&amp;gt;T&amp;lt;/math&amp;gt; is the time when our stream will run out, &amp;lt;math style=&amp;quot;vertical-align: 0px&amp;quot;&amp;gt;r&amp;lt;/math&amp;gt; is the rate (compounded continuously) paid by the bank and  &amp;lt;math style=&amp;quot;vertical-align: -5px&amp;quot;&amp;gt;I(t)&amp;lt;/math&amp;gt; is the desired continuous income stream.  &lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;mw-collapsible mw-collapsed&amp;quot; style = &amp;quot;text-align:left;&amp;quot;&lt;br /&gt;
!Solution: &amp;amp;nbsp;&lt;br /&gt;
|-&lt;br /&gt;
|There isn't much to do here, except identify that &amp;lt;math style=&amp;quot;vertical-align: -0.5px&amp;quot;&amp;gt;T\,=\,5&amp;lt;/math&amp;gt;, &amp;lt;math style=&amp;quot;vertical-align: -5px&amp;quot;&amp;gt;I(t)\,=\,20+30x&amp;lt;/math&amp;gt; and the rate should be written as &amp;lt;math style=&amp;quot;vertical-align: -1px&amp;quot;&amp;gt;r\,=\,10%\,=\,0.10&amp;lt;/math&amp;gt;.&lt;br /&gt;
Click to the final answer to see them in the formula!&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;mw-collapsible mw-collapsed&amp;quot; style = &amp;quot;text-align:left;&amp;quot;&lt;br /&gt;
!Final Answer: &amp;amp;nbsp;&lt;br /&gt;
|-&lt;br /&gt;
|&lt;br /&gt;
::Present value = &amp;lt;math&amp;gt;\int_0 ^T I(t)e^{-rt}\,dt,\,=\,\int_0 ^5 (20+30x)e^{-0.10t}\,dt.&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
[[022_Sample_Final_A|'''&amp;lt;u&amp;gt;Return to Sample Exam&amp;lt;/u&amp;gt;''']]&lt;/div&gt;</summary>
		<author><name>MathAdmin</name></author>
	</entry>
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