Complicated Derivatives

You Should Know

  • Derivatives respect the signs (both positive and negative):

  • Example:

  • Derivatives respect constant multiples:

  • Example:

  • Exponential Rule:

  • Example:

  • Power Rule:

  • Example:

\cdot 3x^2 = 18x^2 </p><ul><li><p><strong>LogarithmicRule:</strong><br></p></li></ul><p></p><ul><li><p>Example:<br></p></li></ul><p></p><h4id="d7228863161141c78b1827a290f4bb67"datatocid="d7228863161141c78b1827a290f4bb67"collapsed="false"seolevelmigrated="true">ChallengeswithDerivativesofComplicatedFunctions</h4><ul><li><p>Thegoalistoexpressthederivativeofcomplicatedfunctionsintermsofthepiecesthatmakeupthecomplicatedfunctions.</p></li><li><p>Forinstance,thederivativesofthefunctions</p></li></ul><p></p><p></p><ul><li><p>areknown,butcomplicationsarisewithproductsoffunctionslike</p></li></ul><p></p><p></p><ul><li><p>Unfortunately,derivativesarenotasfriendlywithmultiplicationanddivisionbyvariables!</p></li></ul><h3id="1b0b3bc11f604602996ea8f74db09561"datatocid="1b0b3bc11f604602996ea8f74db09561"collapsed="false"seolevelmigrated="true">ThePRODUCTRule</h3><p><br></p><ul><li><p>Examples:</p></li></ul><p></p><p></p><p></p><p></p><h3id="3bb27fc3ad03412ca69c6335c1c943a2"datatocid="3bb27fc3ad03412ca69c6335c1c943a2"collapsed="false"seolevelmigrated="true">TheQUOTIENTRule</h3><p><br></p><ul><li><p>Examples:</p></li></ul><p></p><p></p><p></p><p></p><h3id="3abb04f1231e44be9556c248a958cf75"datatocid="3abb04f1231e44be9556c248a958cf75"collapsed="false"seolevelmigrated="true">FunctionCompositionandChainRule</h3><h4id="710a7b7954c94278aa0b908c5e601202"datatocid="710a7b7954c94278aa0b908c5e601202"collapsed="false"seolevelmigrated="true">ReminderonFunctionComposition</h4><ul><li><p>Anunderstandingoffunctioncompositionisvital:</p><ul><li><p>Forfunctions</p></li><li><p></p><ul><li><p><strong>Logarithmic Rule:</strong> <br></p></li></ul><p></p><ul><li><p>Example: <br></p></li></ul><p></p><h4 id="d7228863-1611-41c7-8b18-27a290f4bb67" data-toc-id="d7228863-1611-41c7-8b18-27a290f4bb67" collapsed="false" seolevelmigrated="true">Challenges with Derivatives of Complicated Functions</h4><ul><li><p>The goal is to express the derivative of “complicated” functions in terms of the pieces that make up the “complicated” functions.</p></li><li><p>For instance, the derivatives of the functions</p></li></ul><p></p><p></p><ul><li><p>are known, but complications arise with products of functions like</p></li></ul><p></p><p></p><ul><li><p>Unfortunately, derivatives are not as friendly with multiplication and division by variables!</p></li></ul><h3 id="1b0b3bc1-1f60-4602-996e-a8f74db09561" data-toc-id="1b0b3bc1-1f60-4602-996e-a8f74db09561" collapsed="false" seolevelmigrated="true">The PRODUCT Rule</h3><p><br></p><ul><li><p>Examples:</p></li></ul><p></p><p></p><p></p><p></p><h3 id="3bb27fc3-ad03-412c-a69c-6335c1c943a2" data-toc-id="3bb27fc3-ad03-412c-a69c-6335c1c943a2" collapsed="false" seolevelmigrated="true">The QUOTIENT Rule</h3><p><br></p><ul><li><p>Examples:</p></li></ul><p></p><p></p><p></p><p></p><h3 id="3abb04f1-231e-44be-9556-c248a958cf75" data-toc-id="3abb04f1-231e-44be-9556-c248a958cf75" collapsed="false" seolevelmigrated="true">Function Composition and Chain Rule</h3><h4 id="710a7b79-54c9-4278-aa0b-908c5e601202" data-toc-id="710a7b79-54c9-4278-aa0b-908c5e601202" collapsed="false" seolevelmigrated="true">Reminder on Function Composition</h4><ul><li><p>An understanding of function composition is vital:</p><ul><li><p>For functions</p></li><li><p> f(x) = x^2 + x + 1 </p></li><li><p></p></li><li><p>g(x)=e^{x}</p></li><li><p></p></li><li><p> h(x) = x </p></li><li><p>Thefunctioncompositioncantakeformsuchas:</p></li><li><p></p></li><li><p>The function composition can take form such as:</p></li><li><p> (g \circ f)(x) = g(f(x)) </p></li><li><p>Forexample,calculatedas:<br></p></li><li><p>For example, calculated as: <br> g(f(x)) = e^{x^2 + x + 1} </p></li></ul></li></ul><h4id="21951d2fe2e94883911062b399c829fd"datatocid="21951d2fe2e94883911062b399c829fd"collapsed="false"seolevelmigrated="true">ChainRuleforDifferentiation</h4><ul><li><p>TheChainRuleallowsdifferentiationofcomposedfunctions:</p><ul><li><p>Thechainruleisexpressedas:<br></p></li></ul></li></ul><h4 id="21951d2f-e2e9-4883-9110-62b399c829fd" data-toc-id="21951d2f-e2e9-4883-9110-62b399c829fd" collapsed="false" seolevelmigrated="true">Chain Rule for Differentiation</h4><ul><li><p>The Chain Rule allows differentiation of composed functions:</p><ul><li><p>The chain rule is expressed as: <br> \frac{d}{dx}(f(g(x))) = f'(g(x))g'(x) </p></li><li><p>Thedifferentiationisperformedbydifferentiatingtheouterfunctionwhilekeepingtheinnerfunctionintact,followedbymultiplyingbythederivativeoftheinnerfunction.</p></li></ul></li></ul><h4id="41f6e5ada1fb4d21b4ef3e3d56d5e85c"datatocid="41f6e5ada1fb4d21b4ef3e3d56d5e85c"collapsed="false"seolevelmigrated="true">ChainRuleExamples</h4><ul><li><p>Someexamplesinclude:</p><ul><li><p>Simpleapplicationofthechainrule:</p></li><li><p></p></li><li><p>The differentiation is performed by differentiating the outer function while keeping the inner function intact, followed by multiplying by the derivative of the inner function.</p></li></ul></li></ul><h4 id="41f6e5ad-a1fb-4d21-b4ef-3e3d56d5e85c" data-toc-id="41f6e5ad-a1fb-4d21-b4ef-3e3d56d5e85c" collapsed="false" seolevelmigrated="true">Chain Rule Examples</h4><ul><li><p>Some examples include:</p><ul><li><p>Simple application of the chain rule:</p></li><li><p> \frac{d}{dx} \left( e^{6x^2 + 3x - 4} \right) </p></li><li><p>Furtherapplicationsassumingexplicitfunctionswithderivativesnoted.</p></li></ul></li></ul><h3id="4747d7fb0f004990bec2c2bad4b7036b"datatocid="4747d7fb0f004990bec2c2bad4b7036b"collapsed="false"seolevelmigrated="true">SummaryofDerivativeRules</h3><ul><li><p>Tosummarizeessentialderivativerules:</p><ul><li><p><strong>PowerRule:</strong></p></li><li><p>Further applications assuming explicit functions with derivatives noted.</p></li></ul></li></ul><h3 id="4747d7fb-0f00-4990-bec2-c2bad4b7036b" data-toc-id="4747d7fb-0f00-4990-bec2-c2bad4b7036b" collapsed="false" seolevelmigrated="true">Summary of Derivative Rules</h3><ul><li><p>To summarize essential derivative rules:</p><ul><li><p><strong>Power Rule:</strong> \frac{d}{dx}(x^n) = n x^{n-1} </p></li><li><p><strong>ExponentialRule:</strong></p></li><li><p><strong>Exponential Rule:</strong> \frac{d}{dx}(e^{kx}) = ke^{kx} </p></li><li><p><strong>LogarithmicRule:</strong></p></li><li><p><strong>Logarithmic Rule:</strong> \frac{d}{dx} \ln(x) = \frac{1}{x} </p></li><li><p><strong>ProductRule:</strong></p></li><li><p><strong>Product Rule:</strong> \frac{d}{dx}(f(x)g(x)) = f(x)g'(x) + f'(x)g(x) </p></li><li><p><strong>QuotientRule:</strong></p></li><li><p><strong>Quotient Rule:</strong> \frac{d}{dx}(\frac{f(x)}{g(x)}) = \frac{g(x)f'(x) - f(x)g'(x)}{(g(x))^2} </p></li><li><p><strong>ChainRule:</strong></p></li><li><p><strong>Chain Rule:</strong> \frac{d}{dx}(g(f(x))) = g'(f(x))f'(x) $$

Homework and Application

-Homework 7 includes problems for practice that will be demonstrated in lecture videos, depending on time constraints.