X/(9+11)=4 bc x is the “number” and “9, and 11” means add them together. Put the in parenthesis
Answer:
<em>1+√3</em>
Step-by-step explanation:
Area of the triangle = 1/2 * base * height
Area of the triangle = 1/2 * AC * BD
We need to get AC
AC = AD+DC
Get base AD using SOH CAH TOA
tan 45 = 4/AD
AD = 4/tan45
AD = 4/1
AD = 4
Get DC
tan 30 = 4/DC
DC = 4/tan 30
DC = 4/(1/√3)
DC = 4√3
AC = 4 + 4√3
AC = 4(1+√3)
Get the Area of the triangle
<em>Area = 1/2 * 4 * 4(1+√3)</em>
<em>Area of the triangle = 1+√3</em>
Plug in n = 1 into the nth term formula
a(n) = 4n-1
a(1) = 4*1-1
a(1) = 3
So the first term is 3
The second term will be 7 because we add on 4 each time, as indicated by the slope of 4. This is also known as the common difference.
So the nth term is found by adding 4 to the (n-1)st term, in other words,
a(n) = a(n-1)+4
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In summary, the answer is
a1=3; an=an-1+4
which is choice B
