Find the length of BD and EC. A D 9 8 B с BD = EC =
1 answer:
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Answer:
b = - 2, b = 4
Step-by-step explanation:
Using the distance formula
d =
with (x₁, y₁ ) = M(3, 1) and (x₂, y₂ ) = N(- 1, b)
d =
=
=
Then
= 5 ( square both sides )
16 + (b - 1)² = 25 ( subtract 16 from both sides )
(b - 1)² = 9 ( take square root of both sides )
b - 1 = ± = ± 3 ( add 1 to both sides )
b = 1 ± 3
Then
b = 1 - 3 = - 2 or b = 1 + 3 = 4
Answer: The equation is f(x) = ;
The piece of plastic has to have 10mm of thickness.
Step-by-step explanation: It is known that with 1 mm of thickness, 5% of the intensity is reduced. So, 95% of the light is transmitted.
For each milimetre added, "more" 95% of light is transmitted.
For example, if another milimetre of plastic is added, another 0.95 of light is transmitted:
0.95.0.95 = 0.9025 of light reach the visor
So, the model that relate thickness of plastic and intensity of light is:
f(x) =
in which:
f(x) is the intensity of light;
x is thickness in mm;
Using the equation, the thickness necessary to reduce intensity to 60% is:
f(x) =
0.6 =
log 0.6 = log
x. log (0.95) = log (0.6)
x =
x = 9.95
x ≈ 10
The thickness necessary to reduce intensity of light to 60% is 10mm.