Question

Find the m 12 years ago

Answer 1

@Psymon

Answer 2

So a law of cosines problem. Any idea on the formula for it?

Answer 3

um this one no

Answer 4

Does the math you work with just not give yoiu any explanations and formulas or what?

Answer 5

i explained this a while ago. i have to take tests without learning the lessons because im behind and dont have time

Answer 6

Ah. Sorry.

Answer 7

\[c ^{2} = a ^{2} + b ^{2} - 2ab(cosC)\]

All the little letters are sides. So you just plug in all the sides and solve for C

Answer 8

thats why you are like my hero man, if it wasnt for you, id be toast

Answer 9

:3 So if you can, plug in the numbers for the sides and eventually solve for cos(C).

Answer 10

18.33

Answer 11

18.33=10^2

Answer 12

is that right? i dont know what to do from there

Answer 13

well, when I solved for cosT, I got cosT = .7818.

Answer 14

so...?

Answer 15

\[7^{2}= 10^{2} + 11^{2} - 2(10)(11)(cosT)\]
\[49 = 100 +121 - 220(cosT)\]

Did you make it that far?

Answer 16

i got 49=1(cosT)

Answer 17

Ah. Something went wrong then O.o

Answer 18

i just did the adding and subtracting to get to that

Answer 19

\[49 = 100 + 121 - 220(cosT)\]
\[49 = 221-220(cosT)\]
\[49-221 = -220(cosT)\]
\[-172 = -220(cosT)\]
\[\frac{ -172 }{ -220 } = cosT\]
\[.7818 = cosT\]

Answer 20

so, how do i figure that? i have never encountered this before

Answer 21

Yeah, your error was you subtracted 220 when it is something that cannot be subtracted, it has to be divided. And this means you have to use the inverse cosine function. \[.7818 = cosT \] This means:
\[\cos ^{-1}(.7818) = T\]

Answer 22

my calculator wont calculate that

Answer 23

i cant type that in

Answer 24

I see. The computer calculator should be able to do that. I know the built in simple one on mine can. You should probably see if you can figure out how to do it on the calculator on your computer. But for now, T = 38.6 degrees.

Answer 25

im on a mac book pro. and i have a more basic calculator than the one google gives me

Answer 26

Ah. Yeah, I know nothing about macs, so maybe the calculator on that one wouldnt have it. But yeah, there may be something that can be googled that can help you calculate inverse trig values like that. But yeah, whenever you have sinx, cosx, tanx and you need to solve for x, then you need to be able to do the inverse functions.

Answer 27

ok thats helpful. i need to find an invers trig calculator on the internet or something

Answer 28

Yeah. Inverse sine, inverse cosine, etc may also be called arcsine, arccosine, etc. So if need be you can search that, too.