Question
If $(\text{a}+\text{b}-\text{x})=\text{f}(\text{x}),$ then $\int\limits^\text{b}_\text{a}\text{x f}(\text{x})\text{dx}$ is equal to:
  1. $\frac{\text{a}+\text{b}}{2}\int\limits^\text{b}_\text{a}\text{f}(\text{b}-\text{x})\text{dx}$
  2. $\frac{\text{a}+\text{b}}{2}\int\limits^\text{b}_\text{a}\text{f}(\text{b}+\text{x})\text{dx}$
  3. $\frac{\text{b}-\text{a}}{2}\int\limits^\text{b}_\text{a}\text{f}(\text{x})\text{dx}$
  4. $\frac{\text{a}+\text{b}}{2}\int\limits^\text{b}_\text{a}\text{f}(\text{x})\text{dx}$

Answer

  1. $\frac{\text{a}+\text{b}}{2}\int\limits^\text{b}_\text{a}\text{f}(\text{x})\text{dx}$
Solution:
Let, $\text{I}=\int\limits^\text{b}_\text{a}\text{x}\text{ f}(\text{x})\text{dx}\ ....(\text{i})$
$=\int\limits^\text{b}_\text{a}(\text{a}+\text{b}-\text{x})\text{f}(\text{a}+\text{b}-\text{x})\text{dx}$
$=\int\limits^\text{b}_\text{a}(\text{a}+\text{b}-\text{x})\text{f}(\text{x})\text{dx}\ ....(\text{ii})$
Adding (i) and (ii)
$2\text{I}=\int\limits^\text{b}_\text{a}(\text{x}+\text{a}+\text{b}-\text{x})\text{f}(\text{x})\text{dx}$
$=(\text{a}+\text{b})\int\limits^\text{b}_\text{a}\text{f}(\text{x})\text{dx}$
Hence $\text{I}=\frac{\text{a}+\text{b}}{2}\int\limits^\text{b}_\text{a}\text{f}(\text{x})\text{dx}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A cone whose height is always equal to its diameter is increasing in volume at the rate of $40\ cm^3/ sec.$ At what rate is the radius increasing when its circular base area is $1m^2?$
A die is thrown once. Let $A$ be the event that the number obtained is greater than 3 . Let $B$ be the event that the number obtained is less than 5 . Then $P(A \cup B)$ is
The order of a matrix $\begin{bmatrix}2&\text{amp};5 &\text{amp};7 \end{bmatrix}$ is:
  1. 3 × 3
  2. 1 × 1
  3. 3 × 1
  4. 1 × 3
If the equation of a line $A B$ is $\frac{x-3}{1}=\frac{y+2}{-2}$ $=\frac{z-5}{4}$, find the direction ratios of a line parallel to $A B$.
Choose the correct answer in Exercise.
$\int\sqrt{1+\text{x}^2}\text{dx}$ is equal to
  1. $\frac{\text{x}}{2}\sqrt{1+\text{x}^2}+\frac{1}{2}\text{log}\Bigg|\Big(\text{x}+\sqrt{1+\text{x}^2}\Big)\Bigg|+\text{C}$
  2. $\frac{2}{3}(1+\text{x}^2)^{\frac{3}{2}}+\text{C}$
  3. $\frac{2}{3}\text{x}(1+\text{x}^2)^{\frac{3}{2}}+\text{C}$
  4. $\frac{\text{x}^2}{2}\sqrt{1+\text{x}^2}+\frac{1}{2}\text{x}^2\text{log}\Bigg|\text{x}+\sqrt{1+\text{x}^2}\Bigg|+\text{C}$
$\cos ^{-1}\left(\frac{-1}{2}\right)+2 \sin ^{-1}\left(\frac{-1}{2}\right)$ is equal to
Consider a LPP given by
Minimum Z = 6x + 10y
Subjected to x ≥ 6, y ≥ 2, 2x + y ≥ 10, x ≥ 0, y ≥ 0
Redundant constraints in this LPP are
  1. x ≥ 0, y ≥ 0
  2. x ≥ 6
  3. 2x + y ≥ 10
  4. none of these
The equation xy = 0 in three dimensional space is represented by:
In each of the following, choose the correct answer:
In a box containing 100 bulbs, 10 are defective. The probability that out of a sample of 5 bulbs, none is defective is
Find which of the binary operations are commutative and which are associative.
Consider a binary operation $*$ on $N$ defined as $a * b = a^3 + b^3$. Choose the
correct answer.