broyden:
start point:         7         -7 
nsteps=4 ncalls=9
root=         1          1 
f(root)=         0   3.54e-10 
eps            = 1E-07
f(root).norm() = 3.54138940394932E-10
test passed

newton:
start point:         7         -7 
nsteps=4 ncalls=14
root=         1          1 
f(root)=         0  -1.11e-14 
eps            = 1E-07
f(root).norm() = 1.11022302462516E-14
test passed