Solution:
Let x,y∈[0,1]. We are to find the probability that x2−3xy+2y2>0.
We can factor the quadratic:
x2−3xy+2y2=(x−y)(x−2y)
So, (x−y)(x−2y)>0.
This inequality holds if both factors are positive or both are negative:
Case 1: x−y>0 and x−2y>0
This gives x>y and x>2y.
But x>2y implies x>y, so the only restriction is x>2y.
But x≤1, y≥0, and x>2y.
For y in [0,0.5), x runs from 2y to 1.
Case 2: x−y<0 and x−2y<0
This gives x<y and x<2y.
But x<y implies x<2y (since y<2y for y>0), so the only restriction is x<y.
For y in [0,1], x runs from 0 to y.
So, the region is:
- For y in [0,0.5], x in [2y,1] (from Case 1)
- For y in [0,1], x in [0,y] (from Case 2)
The total area (probability) is:
A=A1+A2
Where
A1=∫y=00.5(1−2y)dy
A2=∫y=01ydy
Compute A1:
A1=∫00.5(1−2y)dy=[y−y2]00.5=(0.5−0.25)−(0−0)=0.25
Compute A2:
A2=∫01ydy=[2y2]01=21
Therefore, the total probability is:
A=0.25+0.5=0.75
So, the answer is 43.