# File "Rsteep".

f = function(x1,x2) { -(x1-2)^2 -(x2-3)^4 }

fx1 = function(x1,x2) { -2*(x1-2) }

fx2 = function(x1,x2) { -4*(x2-3)^3 }

alpha = 0.2

x1list = x2list = c(4)

for (i in 1:10) {

    x1prev = x1list[length(x1list)]
    x2prev = x2list[length(x2list)]

    x1list = c( x1list, x1prev + alpha * fx1(x1prev,x2prev) )
    x2list = c( x2list, x2prev + alpha * fx2(x1prev,x2prev) )

}

plot(x1list, x2list, type='b')