Q. 9. Find the center of mass of the region bounded by the following functions.y=lnx,x=1,x=2,y=0
Calculate xˉ: To find the center of mass, we need to calculate the coordinates (xˉ, yˉ). First, let's find xˉ, which is the average x-value weighted by area.
Find xˉ formula: The formula for xˉ is the integral of x times the density function over the area, divided by the total mass (area). Since density is constant, it cancels out. So, xˉ=(1/Area)×∫abx(y)dy, where y=lnx and the bounds are x=1 and x=2.
Calculate area: We need to find the area first. The area is given by the integral from 1 to 2 of lnxdx.
Calculate Area: Calculating the integral, we get Area = ∫12lnxdx=[xlnx−x]12.
Calculate xˉ: Plugging in the bounds, Area = (2ln2−2)−(1ln1−1)=2ln2−2−(0−1)=2ln2−1.
Calculate integral: Now, we calculate xˉ=Area1∫12xlnxdx.
Evaluate integral: The integral of xlnxdx is 2x2lnx−4x2. So, we need to evaluate this from 1 to 2.
Calculate xˉ: Plugging in the bounds, we get [222ln2−422]−[212ln1−412]=[2ln2−1]−[0−41]=2ln2−1+41.
Simplify xˉ: Now, we plug the area and the integral result into the formula for xˉ. xˉ=(2ln2−11)⋅(2ln2−1+41).
Identify mistake: Simplifying, we get xˉ=2ln2−12ln2−1+41. Wait, there's a mistake here. We didn't multiply x by lnx in the integral for xˉ.