1. Which method would be the simplest way to solve 7x+5y=19 7x-2y=-16? A. (2,1) B. (1,2) C. (7,5) D. (-7,-2)

<img src="https://tex.z-dn.net/?f=%5Cfrac%7B%5Csec%5Cleft%28x%5Cright%29%7D%7B%5Ccos%5Cleft%28x%5Cright%29%7D-%5Cfrac%7B%5Csin%5

DanielleElmas [232]

Answer:

1

Step-by-step explanation:

First, convert all the secants and cosecants to cosine and sine, respectively. Recall that $csc(x)=1/sin(x)$ and $sec(x)=1/cos(x)$ .

Thus:

$\frac{sec(x)}{cos(x)} -\frac{sin(x)}{csc(x)cos^2(x)}$

$=\frac{\frac{1}{cos(x)} }{cos(x)} -\frac{sin(x)}{\frac{1}{sin(x)}cos^2(x) }$

Let's do the first part first: (Recall how to divide fractions)

$\frac{\frac{1}{cos(x)} }{cos(x)}=\frac{1}{cos(x)} \cdot \frac{1}{cos(x)}=\frac{1}{cos^2(x)}$

For the second term:

$\frac{sin(x)}{\frac{cos^2(x)}{sin(x)} } =\frac{sin(x)}{1} \cdot\frac{sin(x)}{cos^2(x)}=\frac{sin^2(x)}{cos^2(x)}$

So, all together: (same denominator; combine terms)

$\frac{1}{cos^2(x)}-\frac{sin^2(x)}{cos^2(x)}=\frac{1-sin^2(x)}{cos^2(x)}$

Note the numerator; it can be derived from the Pythagorean Identity:

$sin^2(x)+cos^2(x)=1; cos^2(x)=1-sin^2(x)$

Thus, we can substitute the numerator:

$\frac{1-sin^2(x)}{cos^2(x)}=\frac{cos^2(x)}{cos^2(x)}=1$

Everything simplifies to 1.

7 0

2 years ago

What is 17/20,19/20, 0.19, 0.24 in order from greatest to least

oksian1 [2.3K]

0.19,0.24,17/20,19/20

3 0

3 years ago

Read 2 more answers

A student was conducting a study to determine how many pagos he would need for the book he is writing. So, he found that the fol

Mkey [24]

Answer:

224 pages

Step-by-step explanation:

The book has pages that are 5.5in x 6.5 in (which holds 300 words)

There are a total of 67,062 words

Equation:

67,062 / 300 = total number of pages

67,062 = 223.54

That means 224 pages, because the last page is partially filled.

If my answer is incorrect, pls correct me!

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-Chetan K

5 0

3 years ago

PLEASE HELP WILL GIVE BRAINLIEST

emmainna [20.7K]

Pi is defined as the ratio of the circumference of any circle to its diameter. As all circles are similar and therefore proportional in dimensions, pi is therefore always the same for all circles and is constant

3 0

2 years ago

Part of arianna’s earnings are based on a 5% commission rate. At the end of the day arianna earned 14.98 in commission. How much

Katarina [22]

Arianna sold for $ 299.6

Solution:

Given that, Part of Arianna’s earnings are based on a 5% commission rate

At the end of the day arianna earned 14.98 in commission

Therefore,

Commission earned = $ 14.98

Commission rate = 5 %

Let "x" be the amount that Arianna sell that day

Therefore, according to question,

5 % of amount earned = 14.98

5 % of "x" = 14.98

Solve the above equation for "x"

$5 \% \times x = 14.98\\\\\frac{5}{100} \times x = 14.98\\\\5x = 14.98 \times 100\\\\5x = 1498\\\\Divide\ both\ sides\ of\ equation\ by\ 5\\\\x = 299.6$

Thus arianna sold for $ 299.6

7 0

3 years ago