Problem 12.1 The value of ¥ð is 3.1415962654. . . . . If
C is the circumference of a circle and r is its radius,
determine the value of r/C to four significant digits.
Solution:
C = 2¥ðr ¢¡ r
C
= 1
2¥ð
= 0.159154943.
To four significant digits we have
r
C
= 0.1592
Problem 12.2 The base of natural logarithms is e =
2.718281828 . . .
(a) Express e to five significant digits.
(b) Determine the value of e2 to five significant digits.
(c) Use the value of e you obtained in part (a) to determine
the value of e2 to five significant digits.
[Part (c) demonstrates the hazard of using roundedoff
values in calculations.]
Solution: The value of e is: e = 2.718281828
(a) To five sig¡¦(»ý·«)
nificant figures e = 2.7183
(b) e2 to five significant figures is e2 = 7.3891
(c) Using the value from part (a) we find e2 = 7.3892 which is
not correct in the fifth digit.
Problem 12.3 A machinist drills a circular hole in a
panel with a nominal radius r = 5 mm. The actual radius
of the hole
