Add tasks for all the new languages

Task/Arithmetic-geometric-mean-Calculate-Pi/Phix/arithmetic-geometric-mean-calculate-pi.phix

@@ -0,0 +1,20 @@
+include bigatom.e
+
+{} = scale(203)
+bigatom a = BA_ONE,
+        n = BA_ONE,
+        g = ba_divide(BA_ONE,ba_sqrt(2)),
+        z = ba_new(0.25),
+        half = ba_new(0.5),
+        x1, x2, var
+for i=1 to 18 do
+?i
+    x1 = ba_multiply(ba_add(a,g),half)
+    x2 = ba_sqrt(ba_multiply(a,g))
+    var = ba_sub(x1,a)
+    z = ba_sub(z,ba_multiply(ba_multiply(var,var),n))
+    n = ba_add(n,n)
+    a = x1
+    g = x2
+end for
+ba_printf(1,"%.200aB\n",ba_divide(ba_multiply(a,a),z))

Task/Arithmetic-geometric-mean-Calculate-Pi/Sidef/arithmetic-geometric-mean-calculate-pi.sidef

@@ -0,0 +1,23 @@
+func agm_pi(digits) {
+    var acc = (digits + 8);
+
+    local Num!PREC = 4*digits;
+
+    var an = 1;
+    var bn = sqrt(0.5);
+    var tn = 0.5**2;
+    var pn = 1;
+
+    while (pn < acc) {
+        var prev_an = an;
+        an = (bn+an / 2);
+        bn = sqrt(bn * prev_an);
+        prev_an -= an;
+        tn -= (pn * prev_an**2);
+        pn *= 2;
+    }
+
+    ((an+bn)**2 / 4*tn).to_s
+}
+
+say agm_pi(100);