First we will find the 11th term
an = a1 + (n-1) * d
a11 = 12 + (11 - 1) * 5
a11 = 12 + 10 * 5
a11 = 12 + 50
a11 = 62

now we use the sum formula...
Sn = (n (a1 + an)) / 2
S11 = (11 (12 + 62)) / 2
S11 = (11 (74)) / 2
S11 = 814/2
S11 = 407

3 0

2 years ago

Read 2 more answers

A 99 ft length of wire is to be cut into 2 pieces, so that the longer piece is eight feet longer than six times the shorter piec

Serhud [2]

here's the solution,

let the length of shorter peice = x

then the lenght of longer peice = 6x + 8

now, we know that the sum of length of peices measures 99 feet,

So,

=》x + 6x + 8 = 99

=》7x = 91

=》x = 13

shorter piece length = 13 feet

longer peice length = 13 × 6 + 8 = 78 + 8 = 86 feet

5 0

2 years ago

OLLEGE

Sophie [7]

Part 1

$(f\circ g)(x)=f(\sqrt{x})=4\sqrt{x}+1$

We need to make sure the radical is defined, meaning the radicand has to be non-negative. Thus, the domain is $\boxed{[0, \infty)}$

Part 2

$(g \circ f)(x)=g(4x+1)=\sqrt{4x+1}$

We need to make sure the radical is defined, meaning the radicand has to be non-negative. Thus,

$4x+1 \geq 0\\\\4x \geq -1\\\\x \geq -\frac{1}{4}$

Thus, the domain in interval notation is $\boxed{\left[-\frac{1}{4}, \infty)}$

8 0

1 year ago