Please help. I will reward brainly

Mathematics

2 answers:

katovenus [111]3 years ago

8 0

Positive, 72 minus negative 9 is the same thing as 72+9, which equals 81. So the answer is positive

Nezavi [6.7K]3 years ago

3 0

Positive. Here's a trick I use.

- + = -
- - = +

You need two lines to make a +, and you can't make one with just -

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Find the perimeter of the polygon with the given vertices x(-1,3) y(3,0) z(-1,-2)

Dvinal [7]

x(-1,3) y(3,0) z(-1,-2)

m = (3 + 1)/(0 - 3) = 4/-3 = -4/3

y - 3 = -4/3(x + 1)

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4 0

3 years ago

Help! How would I solve this trig identity?

NeTakaya

Using simpler trigonometric identities, the given identity was proven below.

<h3>How to solve the trigonometric identity?</h3>

Remember that:

$sec(x) = \frac{1}{cos(x)} \\\\tan(x) = \frac{sin(x)}{cos(x)}$

Then the identity can be rewritten as:

$sec^4(x) - sen^2(x) = tan^4(x) + tan^2(x)\\\\\frac{1}{cos^4(x)} - \frac{1}{cos^2(x)} = \frac{sin^4(x)}{cos^4(x)} + \frac{sin^2(x)}{cos^2(x)} \\\\$

Now we can multiply both sides by cos⁴(x) to get:

$\frac{1}{cos^4(x)} - \frac{1}{cos^2(x)} = \frac{sin^4(x)}{cos^4(x)} + \frac{sin^2(x)}{cos^2(x)} \\\\\\\\cos^4(x)*(\frac{1}{cos^4(x)} - \frac{1}{cos^2(x)}) = cos^4(x)*( \frac{sin^4(x)}{cos^4(x)} + \frac{sin^2(x)}{cos^2(x)})\\\\1 - cos^2(x) = sin^4(x) + cos^2(x)*sin^2(x)\\\\1 - cos^2(x) = sin^2(x)*sin^2(x) + cos^2(x)*sin^2(x)$