Exponential and logarithmic functions

Practice sheet

Fresh questions from the whole chapter, to do on paper.

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  1. Evaluate log⁡416\log_{ 4 } 16.
  2. Solve 6x=216^x = 21. Write the exact answer using a logarithm.
  3. Match each logarithm statement with the same statement written as a power.
    1. log⁡8y=2\log_{ 8 } y = 2
    2. log⁡8y=3\log_{ 8 } y = 3
    3. log⁡8y=−1\log_{ 8 } y = -1
    4. log⁡8y=12\log_{ 8 } y = \tfrac{1}{2}
    1. y=82y = 8^{2}
    2. y=83y = 8^{3}
    3. y=18y = \dfrac{1}{ 8 }
    4. y=8y = \sqrt{ 8 }
  4. The graph of y=3⋅4x+7y = 3\cdot 4^x + 7 has a horizontal asymptote y=cy = c. What is cc?
  5. The graph of y=log⁡4(x−6)+1y = \log_{ 4 }(x - 6) + 1 has a vertical asymptote x=cx = c. What is cc?
  6. Draw the graph of y=1⋅2x+3y = 1 \cdot 2^x + 3: place two points and the asymptote.
  7. A sample of 64 mg of a radioactive substance has a half-life of 2 years. How many mg are left after 6 years?
  8. A dose of 200 mg of a medicine has a half-life of 2 hours. Write the amount A(t)A(t), in mg, left after tt hours.
  9. A sample of 200 mg has a half-life of 2 years. How much is left after 8 years? Round to 2 decimal places.
  10. Evaluate log⁡1020+log⁡105\log_{ 10 } 20 + \log_{ 10 } 5 without a calculator.
  11. Evaluate 2log⁡26−log⁡292\log_{ 2 } 6 - \log_{ 2 } 9 without a calculator.
  12. Which expression is equal to log⁡8(2⋅7)\log_{ 8 }(2 \cdot 7)?
    1. log⁡82+log⁡87\log_{ 8 } 2 + \log_{ 8 } 7
    2. log⁡82⋅log⁡87\log_{ 8 } 2 \cdot \log_{ 8 } 7
    3. log⁡8(2+7)\log_{ 8 }(2 + 7)
    4. 7log⁡82 7 \log_{ 8 } 2