Data update

Task/Nth-root/ANSI-BASIC/nth-root.basic

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+100 REM Nth root
+110 DECLARE EXTERNAL FUNCTION NthRoot
+120 LET X = 144
+130 PRINT "Finding the nth root of"; X; "to 6 decimal places"
+140 PRINT "  x      n        root    x ^ (1 / n)"
+150 PRINT "--------------------------------------"
+160 FOR I = 1 TO 8
+170    PRINT USING "###   ": X;
+180    PRINT USING "####    ": I;
+190    PRINT USING "###.######": NthRoot(I, X, 1.000000E-07);
+200    PRINT USING "    ###.######": X ^ (1 / I)
+210 NEXT I
+220 END
+230 EXTERNAL FUNCTION NthRoot(N, X, Precision)
+240 REM Returns the Nth root of value X to stated Precision
+250 LET X0 = X
+260 LET X1 = X / N ! initial guess
+270 DO WHILE ABS(X1 - X0) > Precision
+280    LET X0 = X1
+290    LET X1 = ((N - 1) * X1 + X / X1 ^ (N - 1)) / N
+300 LOOP
+310 LET NthRoot = X1
+320 END FUNCTION