Problem: If 1−y is used as an approximation to the value of 1+y1,∣y∣<1, the ratio of the error made to the correct value is:
Answer Choices:
A. y
B. y2
C. 1+y1
D. 1+yy
E. 1+yy2
Solution:
Since 1+y1=1−y+1+yy2, the error in using the approximation 1−y is 1+yy2. The ratio of the error to the correct value is, therefore, (1+yy2)/(1+y1)=y2