` int_(0)^(1)int_(0)^(1-x) (x^2+y^2)dxdy`

int_(0)^(2)int_(0)^(x)int_(0)^(y)xydxdydz

int_(0)^(1)x(1-x)^(9y)dx

int_(z=0)^(1)int_(y=0)^(z)int_(x=0)^(y)xy^(2)z^(3)dxdydz is

int_(0)^(1)(1+2x)dx

int_(0)^(1) (1)/(x^(2) +2x+3)dx

int_(0)^(1)(x+1)/(x^(2)+1)dx

int_(0)^(1)(x-1)/(x^(2)-1)dx

int_(-1)^(1)int_(0)^(2)int_(x-2)^(x+2)(x+y+z)dxdydz

int_(1)^(2)int_(0)^(x)(dydx)/(x^(2)+y^(2))

If int_(0)^(1)f(x)dx=1, int_(0)^(1)x f(x)dx=a and int_(0)^(1)x^(2)f(x)dx=a^(2) , then : int_(0)^(1)(a-x)^(2)f(x)dx=