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