area y=x^2,x=y/2
1) Isolate y in y = x2: y = x2
Isolate y in x = y2: y = 2x
Find the intersections: x2 -2x = 0
⇥You can factorize the expression: x2 -2x into: x·(x -2)
⇥Solution obtained: x = 0
⇥1.1) Let's solve in ℝ: x -2 = 0
⇥Solution obtained: x = 2
The area between x2 and 2x on [0, 2] is the integral of the absolute value of their difference
No interior intersection: the difference keeps its sign on the interval
On [0, 2], 2x is above x2: integrate -x2 + 2x
⇥1.2) Let's integrate: ∫(-x2 + 2x)dx
⇥ -∫(x2)dx + ∫(2x)dx
⇥ℹ-∫(x2)dx = -x33‖∫(2x)dx = 2·x22
⇥ -x33 + 2·x22
⇥ℹ2·x22 = 2x22‖2x22 = x2
⇥ -x33 + x2
⇥1.3) Let's evaluate over the interval [0, 2]: (-233 + 22) -(-033 + 02)
⇥ℹ23 = 8‖22 = 4‖-(-033 + 02) = 033 -02
⇥ -83 + 4 + 033 -02
⇥ -8 + 4·33 + 0
⇥ -8 + 123
⇥ 43
The area on [0, 2] is 43
▶Area:   43