Let x be the number of erasers
4 = 20
1 = x
4x = 20
x = 5
therefore there are 5 number of erasers
Answer:
612
Step-by-step explanation:
take 153 and 2 and divide
153/2=76.5
This answer is your rate in mph, so now take this and multiply by hours given
76.5*8=612 use a calculator.
Answer:
Step-by-step explanation:
You know that ...
- cos(θ)² = 1 - sin(θ)²
- tan(θ) = sin(θ)/cos(θ)
- cosine is negative in the third quadrant (where π < θ < 3π/2)
Using what you know about the relationships of these trig functions, you can find ...
cos(θ)² = 1 - ((-√3)/2)² = 1 - 3/4 = 1/4
cos(θ) = -1/2 . . . . . negative square root of 1/4
__
tan(θ) = sin(θ)/cos(θ) = ((-√3)/2)/(-1/2)
tan(θ) = √3
First use the chain rule; take 
. Then
By the power rule,
By the quotient rule,
So
Answer:
√
8
≈
3
Explanation:
Note that:
2
2
=
4
<
8
<
9
=
3
2
Hence the (positive) square root of
8
is somewhere between
2
and
3
. Since
8
is much closer to
9
=
3
2
than
4
=
2
2
, we can deduce that the closest integer to the square root is
3
.
We can use this proximity of the square root of
8
to
3
to derive an efficient method for finding approximations.
Consider a quadratic with zeros
3
+
√
8
and
3
−
√
8
:
(
x
−
3
−
√
8
)
(
x
−
3
+
√
8
)
=
(
x
−
3
)
2
−
8
=
x
2
−
6
x
+
1
From this quadratic, we can define a sequence of integers recursively as follows:
⎧
⎪
⎨
⎪
⎩
a
0
=
0
a
1
=
1
a
n
+
2
=
6
a
n
+
1
−
a
n
The first few terms are:
0
,
1
,
6
,
35
,
204
,
1189
,
6930
,
...
The ratio between successive terms will tend very quickly towards
3
+
√
8
.
So:
√
8
≈
6930
1189
−
3
=
3363
1189
≈
2.828427
