(a) Complete the table of values for \(y = x + \dfrac{90}{x^2}\)
\(x\)
1
1.2
1.5
2
2.5
3
4
5
\(y\)
91
63.7
24.5
16.9
9.625
8.6
(1)
(b) Draw the graph of \(y = x + \dfrac{90}{x^2}\) for \(1 \leqslant x \leqslant 5\)(2)
(c) Use your graph to find an estimate for the solution of \(\dfrac{1}{2}\left(x + \dfrac{90}{x^2}\right) = 15\) that is in \(1 \leqslant x \leqslant 5\) (2)
Mark scheme (a)
Scheme
Marks
41.5, 13
B1
(1)
Mark scheme (b)
Scheme
Marks
M1
correct curve
A1
(2)
Notes
M1: at least 6 points plotted correctly ft from their table
A1: A fully correct curve through all 8 correct points
