function y = luas_tr(a,b,I)
dx = abs((b - a)/I); % Step-size delta x
Luas = 0;
for i = 1:I,
    x1 = a + (i-1)*dx;
    x2 = a + i*dx;
    sisi1 = abs(fungsi(x1));
    sisi2 = abs(fungsi(x2));
    Luas = Luas + (dx*(sisi1+sisi2)/2);
end
y = Luas;