第2266题:用换元法计算定积分
∫04x+32x+1dx\int_0 ^4 \dfrac{x+3}{ \sqrt{2x+1}} dx∫04√2x+1x+3dx .
A. 203\dfrac{20}{3}320
B. 223\dfrac{22}{3}322
C. 253\dfrac{25}{3}325
D. 283 \dfrac{28}{3}328
令 t=2x+1t=\sqrt{2x+1}t=√2x+1 .