1.If the sum of 2 real numbers be x, what is the maximum value of their product?
2.In a right-angled triangle, if
the sum of the lengths of the two adjacent sides of the right angle is 16cm,
what is the maximum area of the triangle?
F.4 MATHS
2009-12-09 6:37 am
回答 (1)
2009-12-09 7:08 am
✔ 最佳答案
1)let x=a+b, find maximun of ab
by苛西不等式
(a+b)/2>=√(ab)
ab<=(a+b)^2/4=x^2/4
but a,b must be positive!
2)
a+b=16, the area of the triangel=ab/2
by苛西不等式
(a+b)/2>=√(ab)
ab<=(a+b)^2/4=16^2/4=64
ab/2<=32
the maximum area of the triangle is 32
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https://hk.answers.yahoo.com/question/index?qid=20091208000051KK01685