This is an arithmetic sequence, since it's pattern is +4.
n1 = 1
d = 4
n = 1 + (n-1)(4) <-------------- This is the formula for the nth term of the sequence.
Hello,
Use the factoration
a^2 - b^2 = (a - b)(a + b)
Then,
x^2 - 81 = x^2 - 9^2
x^2 - 9^2 = ( x - 9).(x + 9)
Then,
Lim (x^2- 81) /(x+9)
= Lim (x -9)(x+9)/(x+9)
Simplity x + 9
Lim (x -9)
Now replace x = -9
Lim ( -9 -9)
Lim -18 = -18
_______________
The second method without using factorization would be to calculate the limit by the hospital rule.
Lim f(x)/g(x) = lim f(x)'/g(x)'
Where,
f(x)' and g(x)' are the derivates.
Let f(x) = x^2 -81
f(x)' = 2x + 0
f(x)' = 2x
Let g(x) = x +9
g(x)' = 1 + 0
g(x)' = 1
Then the Lim stay:
Lim (x^2 -81)/(x+9) = Lim 2x /1
Now replace x = -9
Lim 2×-9 = Lim -18
= -18
(6•2 - 3 - 5•3) - (4•3 + 2•2 - 8)
(12 - 3 - 15) - (12 + 4 - 8)
(9 - 15) - (16 - 8)
(-6) - (8)
-14
The answer would be positive 5
pi·18.6^2·123°/360° - 1/2·18.6^2·SIN(123°) = 226.3
