Question

Solve for:
a) all degrees in solutions
b) theta if 0°≤theta≤360°

2cos^2Ө+11cosӨ=-5

Answer 1

Best way is to suppose cos theta = y

Answer 2

You will get,

2y^2 + 11y - 5 = 0

Solve the quadratic.

Answer 3

oh that works too ? lol

Answer 4

Yes. ;)
That's an easy shortcut.

Answer 5

wait i gotta use quadradic formula ?

Answer 6

Yes.
and when you get the values..

Let's say if you get 2.

use it like this,

cos theta = y
cos theta = 2
theta = cos^-1(2)
and so on. ;)

Answer 7

wait let me get quadratic first -.-

Answer 8

okay..
im leaving soon.
but u may carry on with the same method.

Answer 9

ok ok, not sure if this is correct but
x=-11+-sqrt 11^2-4(2)(5)/2(2) ?

Answer 10

lol i think i need to draw it out

Answer 11

-5.9, 0.4

Answer 12

cos theta = y
cos theta = -5.9
ignore this value,

Use the second one.

Answer 13

cos theta = y
cos theta = 0.42
theta = cos^-1(0.42)
theta = 65.1*

so,

65.1* and 360 - 65.1*

two answers.

Answer 14

wow so fast, @@

Answer 15

make me so confuse lol

Answer 16

anyway i can use the calculator for this ?

Answer 17

Lol.
This is short and easy. that's why i did it fast.
Yes for sure.

Answer 18

Where are you confused?

Answer 19

how? it easy for you but for me it's...

Answer 20

They are just simple steps like i told you.
Use shortcuts. heh.

Which part you don't get?

Answer 21

ok when you move the 5 over for quadratic shouldn't it be +5 ?

Answer 22

i solved the quadratic equation using a calc. lol.

Answer 23

o__0!

Answer 24

How did you do it? what did you plugged in calc?

Answer 25

type it on here so i can see lol :)

Answer 26

Lol, which calc do you have? i am using Casio currently.

Answer 27

TI-84 Plus

Answer 28

My calc can solve quadratic equations too.
we just have to insert the values for a,b,c.

Answer 29

http://www.youtube.com/watch?v=z1jqegsr7dM

Answer 30

How do i execute it and use it?

Answer 31

http://www.youtube.com/watch?v=lRuOSDQoaak&feature=iv&annotation_id=annotation_196031

Answer 32

I have no idea. i never used that calc.

Answer 33

lol =.=!

Answer 34

for some reason I found your very funny lol :))

Answer 35

that had nothing to do with math but oh well :))

Answer 36

Haha, you are correct.
i like being funny.
It keeps the environment cool.. coz math makes people angry and pissed.
hehe.

Answer 37

it does lol, im so pissed today that i did only 3 problems =.= out of 25 lol

Answer 38

props to you :D

Answer 39

Haha, be of luck to you with rest 22.

Lol, thanks.

mind telling me which math is this? calc 1 or calc 2 or something? idk..

Answer 40

Trig lol

Answer 41

my final is 50 questions. Yup..... lol

Answer 42

are there different stages of trig too?
like calc 1 or calc 2..
are there trig 1 or trig 2 something like that too?

Best of luck.
these are easy as pastry.

Answer 43

i dont think so, when im done with trig, im moving on to pre-cal so...

Answer 44

Oh, okay. so this might be after alg2..

Answer 45

easy for youuuu.. lol for me it's hell. and I am so close to failing

Answer 46

yeah

Answer 47

you have taken all the math it seems ?

Answer 48

Lol. no not all math. im almost 16. im not einstein that i will study all math. HAha.
but i have studied much. calc and further.

Answer 49

your only 16 ?

Answer 50

well almost ?

Answer 51

yes. i will turn 16 in oct.

Answer 52

geeeezz genius right here =.=

Answer 53

looooool, no please. im not.

Answer 54

you should be some rocket scientist or something :))

Answer 55

Haha, Noway.
i liked astronomy before.. but im not interested anymore..

Answer 56

or something like that lol :))

Answer 57

so your still in middle school or high school ?

Answer 58

or no school at all cuz ur so freaking genius

Answer 59

Haha, no even close.

You can say HS.. im not in US.. so if you start counting, you can count me in 12th grader.

Answer 60

ohh, so your almost college, wait how come your only almost 16? im confuse now lol

Answer 61

im confuse at everything :))

Answer 62

Oh man! this is so hard to explain everyone. lol.
everyone asks me the same question..
well, i jumped some of my classes while i was in primary and so i ended up so young. -_-

Answer 63

ohhh i see wow :))

Answer 64

My dad made me jump classes.

Answer 65

you gotta be super genius for them to let you jump classes like that, no jokes :)

Answer 66

oh he did? lol

Answer 67

lol, it was his decision. i was way young.

Answer 68

your nickname sounds like your asian, correct me if im wrong :d, just curiosity

Answer 69

Yes! Pakistani.

Answer 70

uhhh is that Japanese? lol

Answer 71

oh pakistan? wow :|

Answer 72

my bad lolo

Answer 73

Yes. Pakistan. lol.

Answer 74

LOL @Japenese thing.

Answer 75

haha lol :))

Answer 76

its somewhere near India i suppose?

Answer 77

http://www.vbmap.org/pictures/middle-east/pakistan/pakistan.gif

http://www.vbmap.org/pictures/middle-east/pakistan/PakistanWorldMap.png

Answer 78

why are we talking about this stuff? 0__0

Answer 79

Haha, math help converted into Geography class. Lol

Answer 80

=.= so true lol

Answer 81

Oh well, so till where you understood the problem?

Answer 82

hehe

Answer 83

im 100% lost......Yupp thanks to you lol

Answer 84

Haha, idk what to say. lol
try reading the whole thing again and tell me what part you don't get.

Answer 85

im trying to program the quadratic..

Answer 86

Ok, cool.

Answer 87

Ok ok, i used the quadratic program and i got -.5 and -5 wtf =.=

Answer 88

LOl.

Answer 89

Use these;

2y^2 + 11y - 5 = 0

Answer 90

what now lol

Answer 91

solve using a quadratic that's all i can say. hehe

Answer 92

got decimals

Answer 93

round them off.
Why you SO confused decimals?
http://i0.kym-cdn.com/photos/images/original/000/089/665/tumblr_l96b01l36p1qdhmifo1_500.jpg

Answer 94

lmao LOL

Answer 95

im so gonna have a nightmare tonight cuz of that pic lol

Answer 96

HAHA. :D

Answer 97

omg i did it lmao...65.1 degrees wow.. im a genius lol

Answer 98

wait why did you ignore the -5.9 ?