Answer:
f(n) = -n^2 -3n +5
Step-by-step explanation:
Suppose the formula is ...
f(n) = an^2 +bn +c
Then we have ...
f(1) = 1 = a(1^2) +b(1) +c
f(2) = -5 = a(2^2) +b(2) +c
f(3) = -13 = a(3^2) +b(3) +c
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Here's a way to solve these equations.
Subtract the first equation from the second:
-6 = 3a +b . . . . . 4th equation
Subtract the second equation from the third:
-8 = 5a +b . . . . . 5th equation
Subtract the fourth equation from the fifth:
-2 = 2a
a = -1
Then substituting into the 4th equation to find b, we have ...
-6 = 3(-1) +b
-3 = b
and ...
1 = -1 +(-3) +c . . . . . substituting "a" and "b" into the first equation
5 = c
The formula is ...
f(n) = -n^2 -3n +5
1/10 in fraction from or 0.1 in decimal form
Answer:
Step-by-step explanation:
The vertex would be (5, 27)
Answer:
Obtuse triangle.
Step-by-step explanation:
Side a = 5
Side b = 2
Side c = 4
Angle ∠A = 108.21° = 108°12'36" = 1.88862 rad
Angle ∠B = 22.332° = 22°19'54" = 0.38976 rad
Angle ∠C = 49.458° = 49°27'30" = 0.86321 rad
Since one angle is above 90 degrees, the triangle is obtuse triangle.
This cannot be an acute triangle.
