Answer:
(a) For the sum X1 + X2, we have:
X1 + X2 = (x1 + e1) + (x2 + e2)
= x1 + x2 + (e1 + e2)
The error in the sum is given by:
e1 + e2 = (x1 + e1) + (x2 + e2) - (x1 + x2)
= (x1 + x2) + (e1 + e2) - (x1 + x2)
= e1 + e2
Therefore, the error in the sum is e1 + e2, as required.
(b) For the difference X1 - X2, we have:
X1 - X2 = (x1 + e1) - (x2 + e2)
= x1 - x2 + (e1 - e2)
The error in the difference is given by:
e1 - e2 = (x1 + e1) - (x2 + e2) - (x1 - x2)
= (x1 - x2) + (e1 - e2) - (x1 + x2)
= e1 - e2
Therefore, the error in the difference is e1 - e2, as required.
(c) Show that the error in a product X1X2 is:
x1x2 - X1X2 ≈ (X1 * e2) + (X2 * e1)
Proof:
We start with the equation:
X1X2 = (x1 + e1)(x2 + e2)
Expanding the right side of the equation, we get:
X1X2 = x1x2 + x1e2 + x2e1 + e1e2
Subtracting x1x2 from both sides, we get:
x1x2 - X1X2 = x1e2 + x2e1 + e1e2
Since e1 and e2 are small compared to x1 and x2, we can ignore the e1e2 term. Therefore, we can approximate the error as:
x1x2 - X1X2 ≈ (X1 * e2) + (X2 * e1)
(d) Show that in a quotient X1 / X2, the error is:
(x1 / x2) - (X1 / X2) ≈ ((e1 * X2) - (e2 * X1)) / (X2)^2
Proof:
We start with the equation:
X1 / X2 = (x1 + e1) / (x2 + e2)
Expanding the right side of the equation, we get:
X1 / X2 = (x1 / x2) + (x1 * e2 - x2 * e1) / (x2)^2 + e1 / x2 - e2 * x1 / (x2)^2
Subtracting (x1 / x2) from both sides, we get:
(x1 / x2) - (X1 / X2) = (x1 * e2 - x2 * e1) / (x2)^2 + e1 / x2 - e2 * x1 / (x2)^2
Simplifying the expression, we get:
(x1 / x2) - (X1 / X2) ≈ ((e1 * X2) - (e2 * X1)) / (X2)^2
This is the error in the quotient.
Step-by-step explanation: