(lg2)^3+(lg5)^2=
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/08/03 17:27:37
(lg2)^3+(lg5)^2=
![(lg2)^3+(lg5)^2=](/uploads/image/z/6038461-37-1.jpg?t=%28lg2%29%5E3%2B%28lg5%29%5E2%3D)
题目没问题?貌似只看过这类的:(lg2)^3+(lg5)^3+3lg5*lg2
a³+b³=(a+b)(a²-ab+b²) (lg2)^3+(lg5)^3+3lg5*lg2 =(lg2+lg5)[(lg2)²-lg2*lg5+(lg5)²]+3lg2*lg5 =(lg10)[(lg2)²-lg2*lg5+(lg5)²]+3lg2*lg5 =(lg2)²-lg2*lg5+(lg5)²+3lg2*lg5 =(lg2)²+2lg2*lg5+(lg5)² =(lg2+lg5)² =(lg10)² =1² =1
a³+b³=(a+b)(a²-ab+b²) (lg2)^3+(lg5)^3+3lg5*lg2 =(lg2+lg5)[(lg2)²-lg2*lg5+(lg5)²]+3lg2*lg5 =(lg10)[(lg2)²-lg2*lg5+(lg5)²]+3lg2*lg5 =(lg2)²-lg2*lg5+(lg5)²+3lg2*lg5 =(lg2)²+2lg2*lg5+(lg5)² =(lg2+lg5)² =(lg10)² =1² =1