Proving the Trigonometric Equation 1-sin2θ/cos2θ = 1-tanθ/1+tanθ

[ming_RICE]

Sorry but i don't know how to use latex yet or to add mathematical symbols somehow.

Homework Statement

Prove that 1-sin2θ/cos2θ = 1-tanθ/1+tanθ

Homework Equations

sin2θ = 2tanθ/1+tan²θ and cos2θ =1-tan²θ/1+tan²θ

I have allready proved from a previous exercise those two above so i pressume they may be useful.

The Attempt at a Solution

1-sin2θ/cos2θ = 1-2tanθ/1+tan²θ/1-tan²θ/1+tan²θ=

i then multiply the fraction with (1+tan2θ) and i am left with

1-2tanθ/1-tan²θ

i have tried various things but i suppose this is the way to go.. maybe not, i don't know, i am stuck. Can someone help me on that one please?

 

[marlon]

Prove that (1-sin2θ)/cos2θ = (1-tanθ)/(1+tanθ)
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just replace the sine and cosine by the relevant equations that you cited.

The exercise is quite straighforeward.

you should come to (1-tanθ)^2/(1-tan^2(θ))

marlon

 

[ming_RICE]

Yes you told me exactly what i did
but for some reason i am stuck at this step. Its not that straight forward for me as it is for you

 

[marlon]

Yes you told me exactly what i did
but for some reason i am stuck at this step. Its not that straight forward for me as it is for you

Again i tell you : redo what you did because you calculated it incorrectly. What you give as your result is already incorrect ! Recalculate the substitutions

ps : please, try to be polite to people that are trying to help you. Otherwise you won't last long here. Just a small piece of advice.

 

[ming_RICE]

Ok so my calculations were wrong i will try and work it out then, thanks.

And btw i admire that you are helping people with their math problems but you did not help me with your first post, capito?

 

[marlon]

Ok so my calculations were wrong i will try and work it out then, thanks.

And btw i admire that you are helping people with their math problems but you did not help me with your first post, capito?

If i didn't help you with my post then why do you say your calculations are wrong ?

We are not going to spoon feed the solution to you. That doesn't serve ANY purpose.
I clearly stated what equation you should get if you did it properly and i also told you where your mistakes were made.

Aside, giving you the solution, there is not much else to say

marlon

 

[ming_RICE]

You said that my calculations were wrong in your second post ... In your first post however you just said what i said, you sounded like a parrot.

 

[ming_RICE]

ok sorry i just read the post again you are right i am just a little dizzy to much math for me those days... :)

 

[marlon]

ok sorry i just read the post again you are right i am just a little dizzy to much math for me those days... :)

So, is the problem solved ?

marlon

 

[ming_RICE]

Yes problem solved