2009 H2 Mathematics Paper 1 Question 6

Graphs and Transformations

Answers

x=0.515  {x=-0.515 \;} or   x=2.45{\; x=2.45}

Full solutions

(i)

(ii)

x26+y23=1x2+2y2=6\begin{gather*} \frac{x^2}{6} + \frac{y^2}{3} = 1 \\ x^2 + 2 y^2 = 6 \\ \end{gather*}
Substituting equation of C1,{C_1,}
x2+2(x2x+2)2=62(x2x+2)2=6x22(x2)2=(x+2)2(6x2)  \begin{gather*} x^2 + 2 \left( \frac{x-2}{x+2} \right)^2 = 6 \\ 2 \left( \frac{x-2}{x+2} \right)^2 = 6 - x^2 \\ 2 \left( x-2 \right)^2 = (x+2)^2(6 - x^2) \; \blacksquare \end{gather*}

(iii)

Solving the equation with a GC,
x=0.515 (3 sf)  or   x=2.45 (3 sf)  \begin{align*} x &= -0.515 \textrm{ (3 sf)} \; \blacksquare \\ \textrm{or } \; x &= 2.45 \textrm{ (3 sf)} \; \blacksquare \\ \end{align*}