Mathematics 9709 · AS & A Level · Logarithmic and exponential functions

Logarithmic and exponential functions — practice question

The variables $x$ and $y$ are related by $a^{2y} = e^{3x+k}$, with $a$ and $k$ constant. A graph of $y$ against $x$ is a straight line.
(a)[1]

Use logarithms to demonstrate that the gradient of the straight line is $\frac{3}{2\ln a}$.

(b)[4]

Using the fact that the straight line passes through the points $(0.4, 0.95)$ and $(3.3, 3.80)$, determine the values of $a$ and $k$.

Worked solution & mark scheme

This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: State or imply $2y\ln a = 3x + k$ and then conclude that the gradient is $\frac{3}{2\ln a}$

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