\(\rm \displaystyle\int_0^{\pi/2} \dfrac{\sqrt{\sin^8 x}}{\sqrt{\sin^8 x}+ \sqrt{\cos^8 x}}dx\) এর মান নির্ণয় করুন।

Question

Question

Answer 1

ধারণা:

\(\rm \displaystyle\int_0^{\pi/2} \dfrac{\sqrt{\sin^8 x}}{\sqrt{\sin^8 x}+ \sqrt{\cos^8 x}}dx\)

গণনা:

ধরি, I = \(\rm \displaystyle\int_0^{\pi/2} \dfrac{\sqrt{\sin^8 (π/2 -x)}}{\sqrt{\sin^8 (π/2 -x)}+ \sqrt{\cos^8 (π/2 -x)}}dx\) ----(i)

⇒ I = \(\rm \displaystyle\int_0^{\pi/2} \dfrac{\sqrt{\cos^8 x}}{\sqrt{\sin^8 x}+ \sqrt{\cos^8 x}}dx\)

⇒ I = \(\dfrac{\pi}{4}\) ----(ii)

(i) এবং (ii) যোগ করে পাই,

⇒ 2I = \(\rm \displaystyle\int_0^{\pi/2} \dfrac{\sqrt{\cos^8 x}+ \sqrt{sin^8x}}{\sqrt{\cos^8 x}+ \sqrt{\sin^8 x}}dx\)

⇒ 2I = \(\rm \displaystyle\int_0^{\pi/2}dx\)

⇒ 2I = \(\rm[x]^\frac{\pi}{2}_0\)

⇒ I = \(\dfrac{\pi}{4}\)