Mathematics, 12.07.2019 01:00, magicalpenguin48

In two or more complete sentences, use your knowledge of the unit circle to describe why the following trigonometric equation is true. tan(-20 degrees) = -tan(20 degrees)

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answered: graymonky12

You have to describe why $\tan (-20^{\circ})=-\tan 20^{\circ}.$

Consider the left side $\tan (-20^{\circ}).$ Angle $-20^{\circ}$ is placed at IVth quadrant and has (see attached diagram for signs of cosines - first sign in brackets and sines - second sign in brackets)

$\cos (-20^{\circ})=\cos (20^{\circ}),\\\sin (-20^{\circ})=-\sin (20^{\circ}).$

Then

$\tan (-20^{\circ})=\dfrac{\sin(-20^{\circ})}{\cos(-20^{\circ})}=\dfrac{-\sin(20^{\circ})}{\cos(20^{\circ})}=-\tan 20^{\circ}.$

In two or more complete sentences, use your knowledge of the unit circle to describe why the followi

answered: Guest

i believe your answer is 99.7% of 7-year-old children are between 46.6 inches and 49.5 inches tall.

answered: Guest

your exact question is kind of difficult to understand, so maybe an example will explain what you're supposed to do? i'll work through the first problem on the worksheet.

suppose you have a tray of 652 brownies, and you have 5 friends that you want to feed without picking favorites. how many brownies can you dole out to each of your friends in equal amounts? how many will be left over for you to eat?

what you're doing here is finding a way to arrange the number 652 as the sum of integer multiple of 5 and some remainder: $652=5q+r$

here $q$ ("q" for quotient) is the number of brownies each of your friends get, and $r$ is the remainder. that's the basic idea behind division.

we break up the number 652 into parts so that the leading digit stands on its own:

652 = 600 + 52

first we check if it's possible to hand out exactly 100 brownies to each friend. with 5 friends, this means we want to know if we can take out 500 brownies from the tray. we can do this 1 time because we have 600 brownies to take from, and when we do that we're left with 100 + 52 brownies to divvy up. so we know that

652 = 1*500 + 152

next we want to know if it's possible to hand out exactly 10 brownies per friend. if we can, we have to remove 50 brownies from the tray each time until we can't. we have 152 brownies left, and we know that 3(50) = 150, so

152 = 3*50 + 2

now we have 2 brownies left in the tray. is it possible to hand 1 out to each of your 5 friends? no, you'd need a minimum of 5 brownies to do that. so the last 2 are yours.

putting everything together, we found that

652 = 1*500 + 3*50 + 2

and we can rearrange this to write

652 = 5*100 + 5*30 + 2

652 = 5(100 + 30) + 2

652 = 5*130 + 2

so $q=130$ and $r=2$ .

you might be more accustomed to the table depicting the algorithm. that's just a compact way of organizing what we've done above. you can consult the image i've attached below.