■ A

A = ∫ y dx = ∫ a*x^n dx = (a/(n+1))*x^(n+1)

0~x1 까지의 면적은,

■ Gx

My = ∫ y*x dx = ∫ a*x^(n+1) dx = (a/(n+2))*x^(n+2)

x = x1 이므로,

My = (a/(n+2))*x1^(n+2)

Gx = (a/(n+2))*x1^(n+2) / (a/(n+1))*x1^(n+1)

■ Gy

Mx = ∫ y*(y/2) dx = ∫ (1/2)*y^2 dx = ∫ (1/2)*a^2*x^(2n) dx
    = (a^2/2)(1/(2n+1))*x^(2n+1)

x = x1 이므로,

Mx = (a^2/2)(1/(2n+1))*x1^(2n+1)

Gy = (a^2/2)(1/(2n+1))*x1^(2n+1) / (a/(n+1))*x1^(n+1)