数学在线解题,急!（一）已知y1=x的二次方-2乘以x的四次方-3；y2=x的三次方-2乘以x的五次方-3,当x=2008时,y1=a,y2=b；当x=-2008时,y1=c,y2=d；求|a-b|+b+d,把你发现或猜想的结论写下来?（二）1/1*3+1/3*5+1/5*7+1/9*11
2019-04-02
数学在线解题,急!
（一）已知y1=x的二次方-2乘以x的四次方-3；y2=x的三次方-2乘以x的五次方-3,当x=2008时,y1=a,y2=b；当x=-2008时,y1=c,y2=d；求|a-b|+b+d,把你发现或猜想的结论写下来?
（二）1/1*3+1/3*5+1/5*7+1/9*11
优质解答
y1是偶函数,a-c=0
y2=(x^3-2)(x^5-3)=x^8-2x^5-3x^3+6
b+d=2x^8+12=8064140
1/1*3+1/3*5+1/5*7+1/9*11
=1/2*(1-1/3+1/3-1/5+1/5-1/7+1/7+1/9+1/9-1/11)
=1/2/1/11
=5/11
y1是偶函数,a-c=0
y2=(x^3-2)(x^5-3)=x^8-2x^5-3x^3+6
b+d=2x^8+12=8064140
1/1*3+1/3*5+1/5*7+1/9*11
=1/2*(1-1/3+1/3-1/5+1/5-1/7+1/7+1/9+1/9-1/11)
=1/2/1/11
=5/11