定积分例题

d(1+4x^2)=8xdx
原式=1/8∫0~1 根号(1+4x^2)d(1+4x^2)
=1/8*(2/3*(1+4x^2)^(3/2))
=1/12(5根号5-1)

原式=1/2(s0~1根号1+4x^2 dx^2)
=1/8[s0~1(1+4x^2)^1/2 d(1+4x^2)]
=1/8*(1+4x^2)^3/2|0~1
=1/8*(5^3/2-1）
=(5根号5-1)/8

原式
=1/8↑8x√(4x^2+1)dx
=1/8↑√4x^2+1d(4x^2)
=1/8[(2/3)(4x^2+1)^3/2]1~0
=(5√5-1)/12