(a)[2]
Show that the gradient of the straight line is $\ln 16$.
(b)[2]
Find the value of $a$.
Mathematics 9709 · AS & A Level · Logarithmic and exponential functions
Logarithmic and exponential functions — practice question
The variables $x$ and $y$ obey the equation $y = 4^{2x-a}$, where $a$ is an integer. As the diagram indicates, the graph of $\ln y$ against $x$ forms a straight line that passes through $(0, -20.8)$, with the second coordinate stated correct to $3$ significant figures.