You have $28, and you want to get half-dollar coins from the bank to give to children who come into your store. What is the most
you can get?
2 answers:
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<h3>Answer: 10*sqrt(30)</h3>
That is the same as writing
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Explanation:
The diagram shows that
- AC = 60
- AD = 50
That must mean DC = AC-AD = 60-50 = 10
We'll use this to help find BD as shown below
AD/BD = BD/DC
AD*DC = BD*BD .... cross multiply
(BD)^2 = AD*DC
BD = sqrt(AD*DC) ..... geometric mean formula
BD = sqrt(50*10)
BD = sqrt(500)
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Now apply the pythagorean theorem to find AB. Focus on triangle ABD.
(AD)^2 + (BD)^2 = (AB)^2
(AB)^2 = (AD)^2 + (BD)^2
(AB)^2 = (50)^2 + (sqrt(500))^2
(AB)^2 = 2500 + 500
(AB)^2 = 3000
AB = sqrt(3000)
AB = sqrt(100*30)
AB = sqrt(100)*sqrt(30)
AB = 10*sqrt(30)
The derivative, f'(x) = 6x^2+1, is never negative, so f(x) is monotonic, hence invertible.
f'(-2) = 6(-2)²+1 = 25
If point (-2, -26) is on the graph of function f(x), and the slope is 25 there, then (-26, -2) is on the graph of f⁻¹(x), and the slope is 1/25 there. The equation of the tangent line throught that point can be written in point-slope form as
... y +2 = (1/25)(x +26)
