Question

can someone help with verifying a trig function?

Answer 1

try us? lols
won't know till you post the question

Answer 2

\[(\sin \theta-\cos \theta)^{2}=1-2\sin^{2} \theta \cot \theta , Verify?\]

Answer 3

i'm going to skip the theta sign so here goes

sin^2 - 2sin*cos + cos^2 = 1 - 2sin^2(cos/sin)

sin^2 - cos^2 = 1

1 - 2 sin*cos = 1 - 2sin(cos

they are equal

make sense?

Answer 4

thank you but just give me a second to make sure i got it

Answer 5

sure thing

Answer 6

how did you get to sin^2 - 2sin*cos + cos^2 = 1 - 2sin^2(cos/sin)

Answer 7

where did the 2sin come from specifically

Answer 8

i foiled the left side of the equation
and tangent is equal to sin/cos
so cot is equal to cos/sin

Answer 9

(a - b)^2
a^2 -2ab + b^2
it's foil

Answer 10

does that make sense?

Answer 11

i think im having trouble with the foiling

Answer 12

umm
do you know how to foil?

(a - b)(a - b)
a^2 - ab - ab + b^2

(sin - cos)(sin - cos)
sin^2 - sin*cos - sin*cos + cos^2
sin^2 - 2sin*cos + cos^2

Answer 13

okay thank you for yor help i see what i was doing wrong, i was foiling wrong, little rusty on the algebra

Answer 14

no problem

Answer 15

hey you have time for another?

Answer 16

sure

Answer 17

Sec^4-tan^4, what trig function is it equal to?

Answer 18

sec is 1/cos

Answer 19

1/cos^4 - sin^4/ cos^4
(1 - sin^4) / cos^4

cos^2 + sin^2 = 1
so cos^2 = 1 - sin^2

[(1 - sin^2)(1 + sin^2)]/ cos^4
(1 + sin^2)/ cos^2

Answer 20

i'm not sure if you can get more simplified than that..

Answer 21

sin^2 = 1 - cos^2

(1 + 1 - cos^2)/ cos^2
(2 - cos^2) / cos^2
2sec^2 - 1
there that's one trig function

Answer 22

the choices are

A) Sec^2
B) csc
C) tan
D) Sec^2+tan^2
E) sin^2
F) sin*tan

Answer 23

the answer is D
where i stopped first
(1 + sin^2)/ cos^2
if you divide that out
you'll get sec^2 + tan^2

Answer 24

ohh man thanks that one was killin me lol just for my own knowledge where do you start first when you see a problem like that? like what goes through your mind first?

Answer 25

i hate doing trig functions
all i can say is something that you've probably heard 100s of times
practice

but seriously, the more you practice, the easier it is

key hints
cos^2 + sin^2 = 1 <-- super big and useful
tan = sin/cos

there are also the rarer ones
half angle formulas

Answer 26

just move the functions around until you see something familiar and you'll see things to cancel out
your object to make it as simple as possible

Answer 27

ok cool keep those in mind i have one question, how did you go from [(1 - sin^2)(1 + sin^2)]/ cos^4 to (1 + sin^2)/ cos^2

Answer 28

i wrote before that line that
cos^2 = 1 - sin^2
which i got from sin^2 + cos^2 = 1 see? very useful

since those are equal, i canceled from top and bottom
does that make sense?

Answer 29

yes i see it now, and i see how you were left with the answer. your helping me out big time lol

Answer 30

lol awesome ^_^

Answer 31

alright ive got another one for you ive been trying it for a while but keep hittin dead ends, got time?

Answer 32

go for it

Answer 33

1/2(1+sin/cos+cos/1+sin) , what trig function is equal?

Sin
cos
tan
csc
sec
cot

Answer 34

cos/1? you sure, caz that's just cos

Answer 35

yup cos/(1+sin)

Answer 36

oh i see you need to use parenthesis rocco, otherwise there's a lot of miss understandings

Answer 37

ohh im sorry

Answer 38

oh and the first part is (1+sin)/cos

Answer 39

1/2(1+tan+cos+cot))

Answer 40

T-T

Answer 41

i feel quite useless....

Answer 42

give me some time, i'm going to write this out, sorry

Answer 43

no problem, and ure not useless dont worry about that lol

Answer 44

rocco
i have no luck for this one :x
sorry!
repost this one

Answer 45

ok no prob, found another one, wanna take a crack at it, i thnk i got half of it?

Answer 46

rofl sure

Answer 47

ok its csc - cot = 1/ (csc + cot) verify

Answer 48

(csc - cot)(csc + cot) = 1
csc^2 - cot^2 = 1
^-- that's another rule you should remember

Answer 49

ohh but can you cross the = sign when verifying?

Answer 50

i'm not sure i understand what you mean?

Answer 51

somewhere i heard that when you verify the = becomes like a wall that you cant cross and only work on either side to make them equal, maybe im just understanding your work wrong

Answer 52

i don't think i've heard that rule

2 + 4 = 8 - 2
if i add 2 on to both sides (crossing?)
i get 6 = 6

do you mean crossing like this?

Answer 53

yea like that

Answer 54

it's perfectly fine
as i just shown up there LOL
6 is equal to 6

so it's fine
cheers ^_^

Answer 55

ohh i see, haha thanks youve been a big help!!!