#1

can anyone help me prove that

tan2

??

tan2

**x**= (2tan**x**) / (1-[tan**x**]^2)??

#2

do your own homework

#3

uhhh

#4

just thought it might be a slightly higher class of homework-mooch than the other stuff we get on here, like "whats 5+2" or "what does freedom mean to me?"

#5

can anyone help me prove that

tan2x= (2tanx) / (1-[tanx]^2)

??

Proofs are feckin' terrible. You know how to do them, right? Make what's on the right look like what's on the left and list the rules you've used every step.

#6

tan(A+B)=(tanA+tanB) / (1-tanAtanB)

Hence

tan 2A = (tanA+tanA) / (1 - tanAtanA)

=(2tanA) / (1-(tanA)^2)

Hence

tan 2A = (tanA+tanA) / (1 - tanAtanA)

=(2tanA) / (1-(tanA)^2)

#7

i could have done that a year ago, but not now

#8

tan(A+B)=(tanA+tanB) / (1-tanAtanB)

Hence

tan 2A = (tanA+tanA) / (1 - tanAtanA)

=(2tanA) / (1-(tanA)^2)

sorry, i'm not allowed to use tan identities, only sin and cos

#9

sorry, i'm not allowed to use tan identities, only sin and cos

I'm three years removed from those, but aren't the tangent identities derived from the sine and cosine ones?

#10

are t-a-n all separate variables?

#11

I'm three years removed from those, but aren't the tangent identities derived from the sine and cosine ones?

yeah, and i don't know how to do it!

*cries like a prepubescent blonde girl*

#12

sorry, i'm not allowed to use tan identities, only sin and cos

You don't like tan? Racist.

#13

are t-a-n all separate variables?

#14

I expected Maths combined with bungee jumping or something.

#15

start with tan2A = sin2A / Cos2A

i cant quite remember the rest from there.

Even though i do have an exam involving this tomorrow!!!

i cant quite remember the rest from there.

Even though i do have an exam involving this tomorrow!!!

#16

I expected Maths combined with bungee jumping or something.

#17

are t-a-n all separate variables?

Hilarious!

#18

I expected Maths combined with bungee jumping or something.

no

#19

Hilarious!

don't laugh at my lack of math skill...

#20

sin2x/cos2x=(2tanx)/(1-(tanx)^2)

sinxcosx/((cosx)^2-(sinx)^2))=(2sinx/2cosx)(1/secx)

sinxcosx/((cosx)^2-(sinx)^2))=(2sinx/2cosx)(cosx)

sinxcosx/((cosx)^2-(sinx)^2))=sinx

?

Sorry that's all I've got.

sinxcosx/((cosx)^2-(sinx)^2))=(2sinx/2cosx)(1/secx)

sinxcosx/((cosx)^2-(sinx)^2))=(2sinx/2cosx)(cosx)

sinxcosx/((cosx)^2-(sinx)^2))=sinx

?

Sorry that's all I've got.

#21

Can you use it in a sentence?

#22

no

Well yeah I noticed after I came in. Thanks for reiterating it though.

#23

Can you use it in a sentence?

"the tan2x F'd you in the A"

#24

are t-a-n all separate variables?

I can't tell if that's epic win or epic fail.

#25

think i got it - thread needs closure!

tan2x = sin2x / cos2x

= 2sinxcosx / cosx^2 - sinx^2

then divide numerator and denominator by cosx^2 to get

= 2tanx / 1 - tanx^2

fulking hellburgers!

tan2x = sin2x / cos2x

= 2sinxcosx / cosx^2 - sinx^2

then divide numerator and denominator by cosx^2 to get

= 2tanx / 1 - tanx^2

fulking hellburgers!

#26

just write LS = RS and you're done.

#27

tan(A+B)=(tanA+tanB) / (1-tanAtanB)

Hence

tan 2A = (tanA+tanA) / (1 - tanAtanA)

=(2tanA) / (1-(tanA)^2)

That.

C3 tomorrow?

#28

That.

C3 tomorrow?

I don't like C3.

C4 is easier. Although the comprehension paper is a load of balls. I don't wanna do the exam tomorrow.

#29

are t-a-n all separate variables?

After being disapointed by the misleading title... this saved the thread

EDIT: How's everyone feeling about C3? Any other further maths students here?

#30

THe answer is 23,,,,,,,,,,,,,,,,or is maybe it's not..........I probably should not listen to me because I'M A LIAR, A LIAR

#31

seeing as im not great at math ill give it a go

can i set x=1?

tan2x = (2tanx) / (1-[tanx ]^2)

tan2(1) = (2tan(1) / (1-[tan(1) ]^2)

tan2=tan2/tan1

tan2= tan2

??

that was just rearranging, im not up on my trig.

can i set x=1?

tan2x = (2tanx) / (1-[tanx ]^2)

tan2(1) = (2tan(1) / (1-[tan(1) ]^2)

tan2=tan2/tan1

tan2= tan2

??

that was just rearranging, im not up on my trig.

#32

This isn't that hard, or it shouldn't be at least. I liked proofs, they were pretty fun actually.

I am in calculus now, and it's not so bad.

I am in calculus now, and it's not so bad.

#33

seeing as im not great at math ill give it a go

can i set x=1?

tan2x = (2tanx) / (1-[tanx ]^2)

tan2(1) = (2tan(1) / (1-[tan(1) ]^2)

tan2=tan2/tan1

tan2= tan2

??

that was just rearranging, im not up on my trig.

You're going about it wrong, you take one side and reaarange it until it says the other side.

#34

C3 sucks balls. i think i'll just shred instead.

*shreds*

*neglects C3*

*gets F*

*works in mcdonalds rest of life*

*dies early of heart disease*

*shreds*

*neglects C3*

*gets F*

*works in mcdonalds rest of life*

*dies early of heart disease*

#35

Math Thread?

And my condolences, McTodd. I hope your next life is better.

And my condolences, McTodd. I hope your next life is better.

#36

Math Thread?

And my condolences, McTodd. I hope your next life is better.

the worst part is, i can't even shred. might as well kill myself now and get it over with.

#37

Seriously, what the **** are you talking about?

#38

#39

what levels that cause i seen it bfore but not that hard ,

#40

"the tan2x F'dmein the A"

Fixed.