Answer:
Barium, Strontium and Beryllium
Explanation:
There are 18 groups in the periodic table and the previous 3 all belong to the same group, group 2 the alkali metals
Silicon is group 14, the carbon group
Aluminum is in the boron group, group 13
Osminium is in the group 8 transition metals
System A has ONE real solution
System B has NO real solutions
System C has ONE real solution
Answer:
Step-by-step explanation:
WITHOUT replacement of first card drawn:
P(a 10 is drawn) = 13/52 = 1/4
P(the next draw is a 10) = 12/52 = 3/13
P(drawing two 10s without replacement of the first draw) = (1/4)(3/13) = 3/52
WITH replacement of first card:
P(two 10s are drawn) = P(first card is a 10)*P(first card is a 10) = (4/13)(4/13) =
16/169
Answer:
You can use either of the following to find "a":
- Pythagorean theorem
- Law of Cosines
Step-by-step explanation:
It looks like you have an isosceles trapezoid with one base 12.6 ft and a height of 15 ft.
I find it reasonably convenient to find the length of x using the sine of the 70° angle:
x = (15 ft)/sin(70°)
x ≈ 15.96 ft
That is not what you asked, but this value is sufficiently different from what is marked on your diagram, that I thought it might be helpful.
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Consider the diagram below. The relation between DE and AE can be written as ...
DE/AE = tan(70°)
AE = DE/tan(70°) = DE·tan(20°)
AE = 15·tan(20°) ≈ 5.459554
Then the length EC is ...
EC = AC - AE
EC = 6.3 - DE·tan(20°) ≈ 0.840446
Now, we can find DC using the Pythagorean theorem:
DC² = DE² + EC²
DC = √(15² +0.840446²) ≈ 15.023527
a ≈ 15.02 ft
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You can also make use of the Law of Cosines and the lengths x=AD and AC to find "a". (Do not round intermediate values from calculations.)
DC² = AD² + AC² - 2·AD·AC·cos(A)
a² = x² +6.3² -2·6.3x·cos(70°) ≈ 225.70635
a = √225.70635 ≈ 15.0235 . . . feet