One of Alberto's zebra danios is 4/3 the length of one of his fancy guppies. Which fish is longer? Explain how you know.
1 answer:
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Answer:
3:
4:
Step-by-step explanation:
Question 3 can be re-written as:
which equals:
Question 4 can be re-written as:
Doing the first 2 brackets gives us:
Expanding these two:
Simplifying it:
The problem can be solved step by step, if we know certain basic rules of summation. Following rules assume summation limits are identical.
Armed with the above rules, we can split up the summation into simple terms:
=> (a) f(x)=28n-n^2
=> f'(x)=28-2n
=> at f'(x)=0 => x=14
Since f''(x)=-2 <0 therefore f(14) is a maximum
(b) f(x) is a maximum when n=14
(c) the maximum value of f(x) is f(14)=196
Armed with the above rules, we can split up the summation into simple terms:
=> (a) f(x)=28n-n^2
=> f'(x)=28-2n
=> at f'(x)=0 => x=14
Since f''(x)=-2 <0 therefore f(14) is a maximum
(b) f(x) is a maximum when n=14
(c) the maximum value of f(x) is f(14)=196