OARLY

Exponential and Logarithm Functions [Video Tutorial]

This tutorial covers material encountered in chapter 5 of the VCE Mathematical Methods Textbook, namely:

  • Exponential functions
  • Index laws
  • Log functions
  • Log laws and change of base

Q1 – Graphs, Intercepts and Asymptotes of Exponential & Logarithm Functions

https://youtu.be/Ie81i5ueu6I

Q2 – Inverses of Exponential & Logarithm Functions

https://youtu.be/xcL1WBWOnE0

Q3 – Exponential & Logarithm Functions

https://youtu.be/gaf_vVNuvrc

Q4 – Solving Exponential & Logarithm Functions

https://youtu.be/XowlqlIQ0L8

Q5 – Intercepts of Logarithm Functions

https://youtu.be/qX-AT291ja8

Q6 – Solving Natural Exponential Function

https://youtu.be/mOzfTNJPb_8

Q7 – Sum and Product of Natural Exponential Functions

https://youtu.be/avJaVSdY0wk

Worksheet

Q1. Sketch the graph of each of the following functions, clearly indicating the axis intercepts and any asymptotes (Note that \(\log_e(x)=\ln(x)\)):

(a) \(f(x)=e^x-3\)

(b) \(f(x)=2^{-x}+4\)

(c) \(g(x)=\dfrac{1}{3}(e^x-4)\)

(d) \(g(x)=5-e^{-x}\)

(e) \(h(x)=\ln(3x+2)\)

(f) \(h(x)=-\ln(x-3)\)

(g) \(j(x)=\ln(2-x)\)

Q2. Find \(f^{-1}\) for each of the following functions:

(a) \(f:\R \to (-3,\infty),\, f(x)=e^{2x}-3\)

(b) \(f:(3,\infty) \to \R,\,f(x)=4\ln(x-3)\)

(c) \(f:(-\frac{1}{2},\infty) \to \R,\,f(x)=\log_{10}(2x+1)\)

(d) \(f:\R \to (3,\infty),\, f(x)=2^x+3\)

Q3. For each of the following functions, find \(y\) in terms of \(x\):

(a) \(\ln(y)=\ln(2x+5)\)

(b) \(\log_2(2y)=3\log_2(3x+1)\)

(c) \(\log_{10}(y)=-3+4\log_{10}(x)\)

(d) \(\ln(y)=2x+3\)

Q4. Solve each equation for \(x\), expressing any logarithms in the answer with base \(e\):

(a) \(3^{2x}-3^{x}-3=0\)

(b) \(log_{10}(3x)-2=0\)

(c) \(5^{2x}-2(5^{x})-3=0\)

Q5. The graph of \(f(x)=2\log_2(2x+1)-5\) intersects the axes at the the points \((a, 0)\) and \((0, b)\) and passes through the point \((c, 3)\) for \(a,b,c \in \R\). Find \(a, b\) and \(c\).

Q6. Solve for \(x\) if \(4e^{2x}=251\).

Q7. Bonus question: Let \(f(x)=\dfrac{1}{2}(e^x+e^{-x})\) and \(g(x)=\dfrac{1}{2}(e^x-e^{-x})\):

(a) Show that \(f\) is an even function

(b) Find \(f(u)+f(-u)\)

(c) Find \(f(u)-f(-u)\)

(d) Show that \(g\) is an odd function

(e) Find \(f(x)+g(x),\, f(x)-g(x),\, f(x)g(x)\)

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