但是是英文A company sells custom embroidered apparel and promotio
2个回答

第一题的意思是x是折扣前的价格,D(x)是折扣后的价格,写出D(x)的区域

Volume ($x) Discount Amount D(x)

$300 ≤ x < $1,000 3% $291 ≤ D(x)< $970

$1,000 ≤ x < $3,000 5% $950 ≤ D(x)< $2850

$3,000 ≤ x < $5,000 7% $2790 ≤ D(x)< $4650

$5,000 ≤ x 10% $4500 ≤ D(x)

2.x接近1000美元时,D(x)的取值

x=1000时,D(x)=950,x越接近1000,不到1000时,是3%的折扣.大于1000后,是5%的折扣,这之间有个差值950~970

接近3000事也一样

我不是很明白这个第二题的目的