The approximate value of $\int_2 x^2 d x$ by using trapezoidal rule with 4 equal intervals, is

The approximate value of $\int_2 x^2 d x$ by using trapezoidal rule with 4 equal intervals, is
  1. $248$
  2. $242.5$
  3. $242.8$
  4. $243$

Solution

Here, $\begin{aligned} n=4, h=\frac{9-1}{4}=2 \\ y_0=f(1)=(1)^2=1 \\ y_1=f(3)=(3)^2=9 \\ y_2=f(5)=(5)^2=25 \\ y_3=f(7)=(7)^2=49 \\ y_4=f(9)=(9)^2=81 \end{aligned}$ by trapezoidal rule $\begin{aligned} \int_1^9 x^2 d x & =\frac{h}{2}\left[y_0+2\left(y_1+y_2+y_3\right)+y_4\right] \\ & =\frac{1}{2} \cdot 2[1+2(9+25+49)+81]=248 \end{aligned}$

Asked in: AP EAMCET 2002

Practice more Definite Integration questions on Aicharya