Find the area bounded by the curve y = sinx between x = 0 and x = 2π
Plot the graph of sinx from 0 to 2π and the required area is shaded
Now observe that the area from 0 to π is above X-axis and the area from π to 2π is below X-axis
The area below X-axis will be negative
Also the areas under sinx from 0 to π and π to 2π are equal in magnitude but they will have opposite sign
Hence if we integrate sinx from 0 to 2π the two areas will cancel out each other as they have opposite signs and we will end up on 0
So either find area under sinx from 0 to π and multiply it by 2 or split the limit 0 to 2π into 0 to π and π to 2π
Here we will split the limit
y = sinx
Integrating from 0 to 2π
Because where c ∈ (a, b)
Here π ∈ (0, 2π)
Also now observe that when x is from π to 2π sinx is negative
Hence for π to 2π sinx will become -sinx
Hence area bounded by sinx from 0 to 2π is 4 unit2