题目 Problem Determine ∫124x2+8x+9 dx\int_1^2 \sqrt{4x^2 + 8x + 9}\,dx∫124x2+8x+9dx (i) (ii) ∫arcosh(3x) dx\int \operatorname{arcosh}(3x)\,dx∫arcosh(3x)dx (3) (4) 题目中文翻译 求 ∫124x2+8x+9 dx\int_1^2 \sqrt{4x^2 + 8x + 9}\,dx∫124x2+8x+9dx (i) (ii) ∫arcosh(3x) dx\int \operatorname{arcosh}(3x)\,dx∫arcosh(3x)dx 解答