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Derivatives of Log Functions. Lesson 4.5. Problem. Consider f(x) = log a x What if we try to use the definition for derivative using the limit No way to break up this portion of the expression to let h → 0. Possible Solution. We know that the derivative is the "slope function"
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Derivatives of Log Functions Lesson 4.5
Problem • Consider f(x) = logax • What if we try to use the definition for derivative using the limit • No way to break up this portion of the expression to let h → 0
Possible Solution • We know that the derivative is the "slope function" • What if we graph y=ln(x) and check the slopes … plotting them
Slope Results • The table at the right shows the values of theslopes at various x values • What function might this be? • Appears to be
Derivative of the Log Function • For the natural logarithm ln(x) • For the log of a different base loga(x)
Examples • Try these sample problems … find the derivative • Don't forget to use the chain rule where applicable
What About ln(-x)? • Consider it a compound function • Apply the chain rule • Thus we see
Conclusion • We now can say • Apply to finding these derivatives
Assignment • Lesson 4.5 • Page 289 • Exercises 1 – 65 EOO