计算.(1)2xy-1/2x^3+2xy+0.5x^3+1/2 (2) 3x+(-5x^3)-(-2x)-5x-(+3x^2)
问题描述:
计算.(1)2xy-1/2x^3+2xy+0.5x^3+1/2 (2) 3x+(-5x^3)-(-2x)-5x-(+3x^2)
答
(1)2 x y - (1 / 2)x ³ + 2 x y + 0.5 x ³ + 1 / 2
= (2 + 2)x y + (1 / 2 - 0.5)x ³ + 1 / 2
= 4 x y + 1 / 2
(2)3 x + (- 5 x ³)-(- 2 x)- 5 x - (+ 3 x ²)
= 3 x - 5 x ³ + 2 x - 5 x - 3 x ²
= (3 + 2 - 5)x - 5 x ³ - 3 x ²
= - 5 x ³ - 3 x ²