The letter is composed of the following curves:
The region bounded by and the positive axis from to .
The region bounded by , and .
The letter is the region of the ellipse .
For the letter with the line , reflect the lines from to and from to about the line forming the desired bounded region..
Find the Area of . That is, find the sum of the areas to six decimal places.
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For the letter R above:
A R = − ∫ 3 6 y 2 − 9 y + 1 8 d y + 3 = − ( 3 y 3 − 2 9 y 2 + 1 8 y ) ∣ 3 6 + 3 = 3 + 2 9 = 2 1 5 .
For the letter O using the ellipse above:
A e = 6 ∫ 3 5 1 − ( x − 4 ) 2 + 1 d x
Let x − 4 − sin ( θ ) ⟹ d x = cos ( θ ) d θ ⟹ A e = 6 ( 2 1 ( θ + 2 1 sin ( 2 θ ) ) ∣ 2 − π 2 π + x ∣ 3 5 ) = 3 ( π + 4 )
For the letter W with the line y = 6 :
Using the symmetry about the line x = 8 :
On the left side of the line x = 8 we have a right triangle and a trapezoid ⟹ A W = 2 ( 3 + 2 9 ) = 1 5
∴ The sum of the areas A R O W = 2 6 π + 6 9 ≈ 4 3 . 9 2 4 7 7 7 .
Note: Using the definite integral for the letter W with the line y = 6 we obtain:
Again, using the symmetry about the line x = 8 ⟹ A W = 2 ( ∫ 0 6 3 y + 2 1 − ( 6 4 2 − y ) d y − ∫ 3 6 8 − ( 3 y + 2 1 ) d y ) =
2 ( 4 1 y 2 ∣ 0 6 − 3 1 ( 3 y − 2 y 2 ) ∣ 3 6 = 2 ( 9 − 2 3 ) = 1 5 .