设多项式ax^5+bx^3+cx+d=M,已知当x=0时,M=-5;当x=3时,M=7;则当x=3时,M=?
问题描述:
设多项式ax^5+bx^3+cx+d=M,已知当x=0时,M=-5;当x=3时,M=7;则当x=3时,M=?
答
是问当x=-3时,M=?据题意:ax^5+bx^3+cx+d=M,已知当x=0时,M=-5,当x=0时则可知:d=M,故d=-5又当x=3时,M=7则ax^5+bx^3+cx-5=7,即a3^5+b3^3+3*c=12当x=-3时,ax^5+bx^3+cx-5=-(a3^5+b3^3+3*c)-5=-12-5=-17...