Marta can vacuum the house in 30 min. It takes her daughter 45 min to vacuum the house. How long would it take them if they
1 answer:
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The equation is 
the -30 expression, is subtracting, if negative, from the 60
if the cosine returned is negative, you'd end up with a +30,
negative * negative = positive
and then the 30 expression will ADD to the 60 amount
so the temperature "t" is highest, when the 30 expression, is
positive and and it's highest
when does that happen, when cosine is negative and at its highest,
well, cosine range is
so the lowest value cosine can provide is -1, when is cosine -1?
well, at
so... let's find a value that makes that expression to
![\bf t=60-30 cos (x \frac{\pi}{6}) \qquad x=6 \\\\ thus \\\\ t=60-30 cos (6 \frac{\pi}{6})\implies t=60-30 cos (\pi ) \\\\ t=60-30[-1]\implies t=60+30\implies t=90](https://tex.z-dn.net/?f=%5Cbf%20t%3D60-30%20cos%20%28x%20%5Cfrac%7B%5Cpi%7D%7B6%7D%29%20%5Cqquad%20x%3D6%0A%5C%5C%5C%5C%0Athus%0A%5C%5C%5C%5C%0At%3D60-30%20cos%20%286%20%5Cfrac%7B%5Cpi%7D%7B6%7D%29%5Cimplies%20t%3D60-30%20cos%20%28%5Cpi%20%29%0A%5C%5C%5C%5C%0At%3D60-30%5B-1%5D%5Cimplies%20t%3D60%2B30%5Cimplies%20t%3D90)
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so...for August, that'll mean
the -30 expression, is subtracting, if negative, from the 60
if the cosine returned is negative, you'd end up with a +30,
negative * negative = positive
and then the 30 expression will ADD to the 60 amount
so the temperature "t" is highest, when the 30 expression, is
positive and and it's highest
when does that happen, when cosine is negative and at its highest,
well, cosine range is
so the lowest value cosine can provide is -1, when is cosine -1?
well, at
so... let's find a value that makes that expression to
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so...for August, that'll mean
Answer:
With alpha 0.95 and 8 degrees of freedom χ²= 2.73
And with alpha 0.05 and 8 degrees of freedom χ²=15.51
Step-by-step explanation:
The significance level ∝ = 1- 0.9 = 0.1
But we need the area of the middle so we divide this significance level with 2
so that we get exactly the middle area .
Dividing 0.1/2= 0.05
So we will have two values for chi square
One with 0.9 + 0.05 = 0.95 alpha and one with 0.05 alpha . This is because the chi square is right tailed.
So with alpha 0.95 and 8 degrees of freedom χ²= 2.73
And with alpha 0.05 and 8 degrees of freedom χ²=15.51
This can be shown with a graph.
