amp;I(x)=∫sin2x(1−cotx)26dxamp;I(x)=∫(sinx−cosx)26dxamp;=∫(tanx−1)26sec2xdx
amp; Let tanx=t⇒sec2xdx=dtamp;=∫(t−1)26dtamp;=−(t−1)6+camp;=(tanx−1)−6+camp;I(x)=1−tanx6+camp;I(0)=3amp;1−tan06+c=3amp;c=−3
I(x)I(12π)amp;=1−tanx6−3amp;=1−tan(12π)6−3amp;=1−(2−3)6−3amp;=3−16−3amp;=3−16−33+3amp;=3−19−33amp;=3−133(3−1)amp;=33