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3 years ago

How do you find direct variation? im having trouble understanding this subject

1 answer:

5 0

I was too just a couple of weeks ago. So direct variation is the constant way to variables change together. EX:
x y
1 2
2 4
3 6
Direct variation must be in the format b=ka where k is a constant. So the direct variation here could be y=2x. Understand?

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How to solve these two problems ？

puteri [66]

8) $\theta$ is -0.896 radians

9) length of arc is 41.91 cm

Solution:

Given that,

$tan\ \theta = \frac{-5}{4}$

$\theta$ is in quadrant 4

To find: $\theta$

From given,

$tan\ \theta = \frac{-5}{4}\\\\\theta = tan^{-1} \frac{-5}{4}\\\\\theta = tan^{-1} (-1.25)\\\\\theta = -51.34$

Thus value of $\theta$ is -51.34 degrees

Convert degrees to radians

$-51.34\ degree = -51.34 \times \frac{ \pi }{180}\ radian\\\\-51.34\ degree = -0.896\ radian$

Thus $\theta$ is -0.896 radians

From given,

radius = 15.4 cm

$\theta = \frac{13 \pi }{15}$

The length of arc when angle in radians is:

$arc\ length = r \times \theta\\\\arc\ length = 15.4 \times \frac{ 13 \pi }{15}\\\\arc\ length = 15.4 \times 2.721\\\\arc\ length = 41.91$

Thus length of arc is 41.91 cm

4 0

3 years ago

A King in ancient times agreed to reward the inventor of chess with one grain of wheat on the first of the 64 squares of a chess

statuscvo [17]

Let's start by visualising this concept.

Number of grains on square:
1 2 4 8 16 ...

We can see that it starts to form a geometric sequence, with the common ratio being 2.

For the first question, we simply want the fifteenth term, so we just use the nth term geometric form:
$T_n = ar^{n - 1}$
$T_{15} = 2^{14} = 16384$

Thus, there are 16, 384 grains on the fifteenth square.

The second question begs the same process, only this time, it's a summation. Using our sum to n terms of geometric sequence, we get:
$S_n = \frac{a(r^{n} - 1)}{r - 1}$
$S_{15} = \frac{2^{15} - 1}{2 - 1}$
$S_{15} = 2^{15} - 1 = 32767$

Thus, there are 32, 767 total grains on the first 15 squares, and you should be able to work the rest from here.

6 0

3 years ago

Read 2 more answers

When Cullen cleaned behind his dresser, he found 73 cents, all in nickels and pennies. There were 25 coins. How many were nickel

Georgia [21]

Let n = number of nickels, and p = number of pennies.
The number of coins is 25, so we get this equation.
n + p = 25

The value of the coins is 0.05 per nickel, and 0.01 per penny.
0.05n + 0.01p = 0.73

Now you have a system of equations.

n + p = 25
0.05n + 0.01p = 0.73

Solve the first equation for n:
n = 25 - p

Now substitute into the second equation.

0.05(25 - p) + 0.01p = 0.73

1.25 - 0.05p + 0.01p = 0.73

-0.04p = -0.52

p = 13

There were 13 pennies.
Now we substitute 13 for p in n + p = 25 to find out the number of nickels.

n + 13 = 25
n = 12

There are 13 pennies and 12 nickels.

Check: 13 pennies and 12 nickels does total 25 coins.
13 * 0.01 + 12 * 0.05 = 0.13 + 0.60 = 0.73
The value is $0.73.
Our answer is correct.

5 0

3 years ago

Which symbol makes the statement true? 125.32 ____ 125.093 < > = ≥

Alexandra [31]

Hello :
125.32 > 125.093 .. because : 3 > 0

4 0

3 years ago

Read 2 more answers

Write 41/11 as a decimal

dimaraw [331]

41/11

Simply use your calculator

3.727272....

8 0

3 years ago