Date | None Specimen | Marks available | 7 | Reference code | SPNone.2.sl.TZ0.9 |
Level | SL only | Paper | 2 | Time zone | TZ0 |
Command term | Sketch and Write down | Question number | 9 | Adapted from | N/A |
Question
Let h(x)=2x−1x+1h(x)=2x−1x+1 , x≠−1x≠−1 .
Find h−1(x)h−1(x) .
(i) Sketch the graph of h for −4≤x≤4−4≤x≤4 and −5≤y≤8−5≤y≤8 , including any asymptotes.
(ii) Write down the equations of the asymptotes.
(iii) Write down the x-intercept of the graph of h .
Let R be the region in the first quadrant enclosed by the graph of h , the x-axis and the line x=3x=3.
(i) Find the area of R.
(ii) Write down an expression for the volume obtained when R is revolved through 360∘360∘ about the x-axis.
Markscheme
y=2x−1x+1y=2x−1x+1
interchanging x and y (seen anywhere) M1
e.g. x=2y−1y+1x=2y−1y+1
correct working A1
e.g. xy+x=2y−1xy+x=2y−1
collecting terms A1
e.g. x+1=2y−xyx+1=2y−xy , x+1=y(2−x)x+1=y(2−x)
h−1(x)=x+12−xh−1(x)=x+12−x A1 N2
[4 marks]
A1A1A1A1 N4
Note: Award A1 for approximately correct intercepts, A1 for correct shape, A1 for asymptotes, A1 for approximately correct domain and range.
(ii) x=−1x=−1 , y=2y=2 A1A1 N2
(iii) 1212 A1 N1
[7 marks]
(i) area=2.06area=2.06 A2 N2
(ii) attempt to substitute into volume formula (do not accept π∫bay2dxπ∫bay2dx ) M1
volume =π∫312(2x−1x+1)2dx=π∫312(2x−1x+1)2dx A2 N3
[5 marks]