If the area between the curves { x 2 + y 2 = 3 ∣ x ∣ + ∣ y ∣ = 3 is ( λ × π − ϕ ) s q . u n i t s ,
then find the value of λ × ϕ
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Pranjal, Do you study at FIITJEE?
This is the graph of the given system of equations:
x 2 + y = 3 and the red colour represents the curve ∣ x ∣ + ∣ y ∣ = 3 1 / 4 .
where the blue colour represents the circleNow the shaded region is the required area which is given by 4 × ( ∫ 0 3 3 − y 2 − ( 3 1 / 4 − ∣ y ∣ ) 2 d x ) = 3 π − 2 . So required value is 3 × 2 = 6 .
NOTE: A better phrasing would be ( λ × π + ϕ ) to avoid ambiguity which would yield the answer -6 since it is unstated whether ϕ > 0 or ϕ < 0 .
Circl equation is x^2 + y^2 = 3 not x^2 + y = 3. Please correct it.
i think all solution involve a bit complex integrals.
The Area required = area of circle -4*area of curve in first quadrant
The latter is readily evaluated by taking curve in first quadrant
And using integral of ydx!
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We are going to use symmetry, and definite integration (using walli's) to get the answer
Area between curves = 4 × Area between curves in first quadtant
Parametric form of curve is ( 3 cos 4 θ , 3 sin 4 θ )
d y = 4 3 sin 3 θ cos θ d θ
= 4 × (Area under circle-Area under curve)
= 4 × ( 4 3 π − ∫ 0 π 2 1 2 cos 5 θ sin 3 θ d θ
= 3 π − 4 8 × 8 × 6 × 4 × 2 ( 4 × 2 ) ( 2 ) (Using walli’s formula)
= 3 π − 2
λ = 3 , ϕ = 2
λ × ϕ = 6