Let S={(x,y)โRรR:xโฅ0,yโฅ0,y2โค4x,y2โค12โ2xย andย 3y+8โxโค58โ}. If the area of the region S is ฮฑ2โ, then ฮฑ is equal to
(A)
217โ
(B)
317โ
(C)
417โ
(D)
517โ
Detailed Solution
The region S is in the first quadrant. The curves are P1โ:y2=4x and P2โ:y2=12โ2x. They intersect where 4x=12โ2xโ6x=12โx=2,y=22โ.
The line is 3y+22โx=102โ. At x=2, 3(22โ)+22โ(2)=102โ, so the line also passes through (2,22โ).
For yโ[0,22โ], the region is bounded on the left by x=y2/4 and on the right by the line x=5โ22โ3yโ (since for y<22โ, the line is more restrictive than the curve x=6โy2/2).
Area =โซ022โโ(xrightโโxleftโ)dy=โซ022โโ(5โ22โ3yโโ4y2โ)dy
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