下列属于杂食性动物的是（ ）
A：鼠
B：骆驼
C：鳄鱼
D：河马
钠作为一种重要原料，可用于制造许多在国防工业上有重要用途的金属．下列关于钠的说法不正确的是（ ）
已知函数f（x）=|x﹣m|，关于x的不等式f（x）≤3的解集为﹣1，5．
（1）求实数m的值；
（2）已知a，b，c∈R，且a﹣2b+2c=m，求a2+b2+c2的最小值．
请运用“求索真理的历程”的相关知识分析同学们的讨论。
A
The Cartoon Museum
Come and see the best of British cartoon art. There is something for everyone—including popular cartoon characters and a great shop full of funny books and cards.
Price: ￡4.00
Opening time:
Tuesday – Saturday 10:30-17:30
Sunday 12:00-18:00
Cox's Hotel
Tel: 01789 404600
E-mail: info@coxshotel.co.uk
Website: www.coxshotel.co.uk
Coffee shop: 9:00am-6:00pm
Tea room: 10:30am-5:30pm
Pub: 12:00- midnight (1:30am on Friday/Saturday)
Stratford Butterfly(蝴蝶)Farm
Tel: 01789 299288
E-mail: sales@butterflyfarm.co.uk
Visit: www.butterflyfarm.co.uk www.jxyyjx.com
Price: ￡5.50 adult ￡4.50 child ￡16 family
Opening Hours: Summer 10am-6am
Winter 10am-4:30pm
已知：x∈R，a=x2﹣1，b=4x+5．求证：a，b中至少有一个不小于0．
