若(x²+nx+3)(x²-3x+m)的展开式中不含x²和x³项,求m,n的值 急,速求,
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/24 16:23:07
![若(x²+nx+3)(x²-3x+m)的展开式中不含x²和x³项,求m,n的值 急,速求,](/uploads/image/z/1261307-11-7.jpg?t=%E8%8B%A5%EF%BC%88x%26%23178%3B%2Bnx%2B3%29%28x%26%23178%3B-3x%2Bm%29%E7%9A%84%E5%B1%95%E5%BC%80%E5%BC%8F%E4%B8%AD%E4%B8%8D%E5%90%ABx%26%23178%3B%E5%92%8Cx%26%23179%3B%E9%A1%B9%2C%E6%B1%82m%2Cn%E7%9A%84%E5%80%BC+%E6%80%A5%2C%E9%80%9F%E6%B1%82%2C)
若(x²+nx+3)(x²-3x+m)的展开式中不含x²和x³项,求m,n的值 急,速求,
若(x²+nx+3)(x²-3x+m)的展开式中不含x²和x³项,求m,n的值 急,速求,
若(x²+nx+3)(x²-3x+m)的展开式中不含x²和x³项,求m,n的值 急,速求,
x²项:mx² + nx * (-3x) + 3x² =(m-3n+3)x²
和x³项:x² * (-3x) + nx *x² =(n-3)x³
则m-3n+3=0,n-3=0;
解得m=6,n=3.
(x²+nx+3)(x²-3x+m)展开后为:x4+(n-3)x3+(m-3n+3)x2+(mn-9)x+3m
展开式中若不含x2,x3项,则n-3=0且m-3n+3=0,解得m=6,n=3