Date | November 2015 | Marks available | 2 | Reference code | 15N.2.hl.TZ0.8 |
Level | HL only | Paper | 2 | Time zone | TZ0 |
Command term | Find | Question number | 8 | Adapted from | N/A |
Question
The continuous random variable XX has the probability distribution function f(x)=Asin(ln(x)), 1≤x≤5f(x)=Asin(ln(x)), 1≤x≤5.
Find the value of AA to three decimal places.
Find the mode of XX.
Find the value P(X≤3|X≥2)P(X≤3|X≥2).
Markscheme
A∫51sin(lnx)dx=1A∫51sin(lnx)dx=1 (M1)
A=0.323 (3 dp only)A=0.323 (3 dp only) A1
[2 marks]
either a graphical approach or f′(x)=cos(lnx)x=0 (M1)
x=4.81(=eπ2) A1
Note: Do not award A1FT for a candidate working in degrees.
[2 marks]
P(X≤3|X≥2)=P(2≤X≤3)P(X≥2)(=∫32sin(ln(x))dx∫52sin(ln(x))dx) (M1)
=0.288 A1
Note: Do not award A1FT for a candidate working in degrees.
[2 marks]
Total [6 marks]