4∫01(13+x2+1+x2)dx–3 loge (3) is equal to : [2025]
(3)
Let f(x)=13+x2+1+x2
=3+x2–1+x23+x2–1–x2=3+x2–1+x22
∴ 4∫01f(x)dx=4∫013+x2–1+x22dx
=2[∫013+x2dx–∫011+x2dx]
=2[x23+x2+32 loge |x+3+x2|–x21+x2–12 loge |x+1+x2|]01
=2+3 loge 3–2–loge (1+2)–3 loge 3
=2+3 loge 3–2–loge (1+2)–32 log 3
=2–2–loge (1+2)+32 loge 3
=2–2–loge (1+2)+3 loge 3
∴ 4∫01f(x)dx–3 loge 3=2–2–loge (1+2).