Question

Rewrite with only sin x and cos x.

sin 2x - cos x

Answer 1

@e.mccormick can you help me plz

Answer 2

Use identity... sin2x=2sinxcosx....
So youre answer is 2sinxcosx - cosx

(unless if you want to factor it a little by factoring out a cosx... You get
cosx(2sinx-1)... That doesnt really matter though) the better answer is the one on the top

Answer 3

@Gerardo_cast23 the answer is not avalable plz come back

Answer 4

Allrighty. hmm wierd.
What are the answers given?

Answer 5

2 sin x cos2x

sin x

cos x (2 sin x - 1)

2 sin x

Answer 6

Then yeah its the third one.. Look at the bottom paragraph of the first answer/response I gave. Do you understand it?

Answer 7

oh thanks

Answer 8

wait

Answer 9

can you help with another

Answer 10

Yeah sure

Answer 11

Verify the identity.

cot (x minus pi divided by two) = -tan x

Answer 12

and can you show work plz

Answer 13

ok give me a little bit of minutes; i havent taken trig for a year now lol

Answer 14

Here's a little cheat sheet of Trig identities... The asnwer can be seen under co-function identities but I bet youre teacher wants the answer written out in a different manner. Wait a little

Answer 15

Sorry forgot to attach the link lol http://www.sosmath.com/trig/Trig5/trig5/trig5.html

Answer 16

so what now?

Answer 17

so it tanx?

Answer 18

r u there?

Answer 19

Yeah sorry I was working it out
And well it says to verify the equation....Heres the work in the next response. I think its tanx but your problem says its -tanx.. Lets see...

Answer 20

\[\cot(x-\pi/2)= -tanx\]
\[cotx=\frac{ cosx }{ sinx }\]
\[\cot(x-\pi/2) = \frac{ cosx-\pi/2 }{ sinx-\pi/2 }\]
SO use identity
\[\cos(a-B)=cosacosB+sinasinB\] and\[\sin(a-B)=sinacosB-cosasinB\] (IM still writing but heres half of it

Answer 21

so a is x... and B is the pie/2 so now we plug in and solve...\[\frac{ cosxcos \pi /2+sinxsin \pi /2 }{ sinxcos \pi/2 -cosxsin \pi/2 }\]
Now solve for the ones you know.... cos pie/2=0 and sin pie/2 is 1.... you should be left with -sinx/cosx... which is the same as -tanx

Answer 22

whew that was a long one

Answer 23

can you help me with another, your good

Answer 24

@Gerardo_cast23 ?

Answer 25

haha thank you. and it depends how long is it.. I should be dowmstairs eatinglunch right now>.< I just got out of my free period/calculus class and now im in lunch

Answer 26

oh

Answer 27

ill post and you decide ok?

Answer 28

Verify the identity (1+ sinx)/(cos x) + (cos x)/(1+sin x) = 2 sec x?

Answer 29

is it too long?

Answer 30

yeah I think it is. Im very sorry; I honestly dont know where to start on this problem... you pretty much have to guess and check... Sorry. yeah im going to go to Lunch. To start on this problem I would start at the left hand side; 2secx... by saying that.. Hopefully this helps instead of me explaining it http://www.algebra.com/algebra/homework/Trigonometry-basics/Trigonometry-basics.faq.question.424507.html