1.13: Complete the table of values for y = 2x + 1 + 2/x²

4PM1/2R/November/2020 — Question 4 · 11 marks

(a) Complete the table of values for
y=2x+1+2x2y = 2x + 1 + \frac{2}{x^2}
Give your answers to 2 decimal places where appropriate.
x\displaystyle x0.5\displaystyle 0.51\displaystyle 11.5\displaystyle 1.52\displaystyle 22.5\displaystyle 2.53\displaystyle 33.5\displaystyle 3.5
y\displaystyle y5\displaystyle 56.32\displaystyle 6.328.16\displaystyle 8.16
(2)
(b) On the grid opposite, draw the graph of
y=2x+1+2x2for0.5x3.5y = 2x + 1 + \frac{2}{x^2} \quad \text{for} \quad 0.5 \leq x \leq 3.5
(2)
(c) Use your graph to obtain estimates, to 1 decimal place, of the roots of the equation
2x+2x2=7in the interval0.5x3.52x + \frac{2}{x^2} = 7 \quad \text{in the interval} \quad 0.5 \leq x \leq 3.5
(2)
(d) By drawing a suitable straight line on the grid, obtain estimates, to 1 decimal place, of the roots of the equation
3x2+2x2=5in the interval0.5x3.5\frac{3x}{2} + \frac{2}{x^2} = 5 \quad \text{in the interval} \quad 0.5 \leq x \leq 3.5
(5)