9514 1404 393
Answer:
sum = ∑[n=1,5] 4^(n-4)
Step-by-step explanation:
First of all, you need to be able to describe the n-th term.
Here, we have ...
term #: 1, 2, 3, 4, 5
value: 4^-3, 4^-2, 4^-1, 4^0, 4^1
That is, the exponent of 4 is 4 less than the term number. So, the n-th term is 4^(n-4). The sum of the 5 terms shown is then ...
Answer:
n = -7
Step-by-step explanation:
Solve for n:
-3 n - 5 = 16
Hint: | Isolate terms with n to the left-hand side.
Add 5 to both sides:
(5 - 5) - 3 n = 5 + 16
Hint: | Look for the difference of two identical terms.
5 - 5 = 0:
-3 n = 16 + 5
Hint: | Evaluate 16 + 5.
16 + 5 = 21:
-3 n = 21
Hint: | Divide both sides by a constant to simplify the equation.
Divide both sides of -3 n = 21 by -3:
(-3 n)/(-3) = 21/(-3)
Hint: | Any nonzero number divided by itself is one.
(-3)/(-3) = 1:
n = 21/(-3)
Hint: | Reduce 21/(-3) to lowest terms. Start by finding the GCD of 21 and -3.
The gcd of 21 and -3 is 3, so 21/(-3) = (3×7)/(3 (-1)) = 3/3×7/(-1) = 7/(-1):
n = 7/(-1)
Hint: | Simplify the sign of 7/(-1).
Multiply numerator and denominator of 7/(-1) by -1:
Answer: n = -7
Answer:
Surface area = 70π cm²
Step-by-step explanation:
Surface area = πr² + πrl
Surface area = (π × 5 × 5) + (π × 5 × 9)
Surface area = (25π) + (45π)
Surface area = 70π cm²
First pic: x=27
second pic: x=15
