Let the point (p,p+1) lie inside the region E=(x,y):3-x≤ y≤ √9-x^2,0≤ x≤ 3. If the set of all values of p is the interval (a,b), then b^2+b-a^2 is…
JEE Main 2023 — Mathematics Coordinate Geometry
2023integermedium
Let the point (p,p+1) lie inside the region E=(x,y):3−x≤y≤9−x2,0≤x≤3. If the set of all values of p is the interval (a,b), then b2+b−a2 is equal to ________.
Official previous-year question
Held on 6 Apr 2023 · Verified 6 Jul 2026.
Did you get this right?
Sign in to track your attempts and accuracy.
Solution
Given,
The point (p,p+1) lie inside the region E=(x,y):3−x≤y≤9−x2,0≤x≤3,
And the set of all values of p is the interval (a,b),
Now by observation (p,p+1) lies on y−x=1,
Also point (p,p+1) lies on x+y=3
So, solving y−x=1 and x+y=3 we get, P(1,2)
Again given point (p,p+1) lies on x2+y2=9
So, solving y−x=1 and x2+y2=9, we get
x2+(1+x)2=9
⇒2x2+2x−8=0
⇒x2+x−4=0.........(i)
⇒x=2−1±1+4⋅4=217−1
Hence, p∈(1,217−1)
Now on comparing with p∈(a,b) we get,
⇒a=1,b2+b=4 [using (i)]
Hence, the value of b2+b−a2=4−1=3
Your note
Sign in to keep a private note on this question. Nothing you write is ever public.