Trig (1 Viewer)

[cookiez69]

Hey guys so I'm a bit confused on something.

So here's two separate questions:



So i've tried using the transformation method, and I've expressed the first question in the form rsin(theta - x). I've made this judgement based upon the sign in the middle, and I'm not sure if thats the right method of how I'm supposed to decide, which form to use.

In the second question, i also thought the form rsin(theta - x) would work, but it turns out I was actually meant to use rsin(theta + x).

How do I determine which form to use? I don't really want to use the t-results method, but I might have to swap to it if its more reliable.

 

[braintic]

Hey guys so I'm a bit confused on something.

So here's two separate questions:



So i've tried using the transformation method, and I've expressed the first question in the form rsin(theta - x). I've made this judgement based upon the sign in the middle, and I'm not sure if thats the right method of how I'm supposed to decide, which form to use.

In the second question, i also thought the form rsin(theta - x) would work, but it turns out I was actually meant to use rsin(theta + x).

How do I determine which form to use? I don't really want to use the t-results method, but I might have to swap to it if its more reliable.

You are only 'meant' to use a particular form if the question instructs you to do so. If it doesn't, you are free to choose.

 

[AnimeX]

Yea, so it should work regardless of which one you use.
Not sure why the 2nd one wanted + =S

 

[cookiez69]

You are only 'meant' to use a particular form if the question instructs you to do so. If it doesn't, you are free to choose.

Yeah, it didn't give me a particular form. I chose my own one, but only one specific form worked. I must've done something wrong so I'll go back and redo the working out.

 

[obliviousninja]

Yeah, it didn't give me a particular form. I chose my own one, but only one specific form worked. I must've done something wrong so I'll go back and redo the working out.

Remember to never 'cross things out' ie, divide sinx and cosx, as solutions may be lost.

 

[themoonspretty]

Or you can simply use the t-rule

 

[braintic]

Or you can simply use the t-rule

Why 'simply' ?

Also, you do know that the t-results would not give all of the answers in the 2nd equation?

 

[levaly]

Here is a step by step solution to #2:
http://www.symbolab.com/solutions/t...θ\right)-\cos\left(θ\right)=1, 0\le θ\le 2\pi

 

[hit patel]

hey there
for 1 Use R sin (theta- alpha)
Now this expand this using sum of angles formula
Now equate both sides and find commonalities.
Then square the 2 trigonmetric R forms received .
Then Add them to get R^2= something.
Then Find R
Then Sub R back into the commonality equation.
Then find Alpha.
Then Use the form of R Sin (theta - alpha) where you already know alpha and R however you donot know theta.
Now its simple. Sorry If this didn't explain nicely BUT THIS METHOD IS CALLED AUXILIARY ANGLE METHOD AND LOOKS LIKE YOU KNOW A BIT so google for method on how to do it and use Rsin(theta-alpha) or Rcos (theta + alpha).

 

[braintic]

Here is a step by step solution to #2:
http://www.symbolab.com/solutions/t...θ\right)-\cos\left(θ\right)=1, 0\le θ\le 2\pi

Why are you promoting this website?
You would certainly not want to recommend it as a teaching tool when it solves the equation sin x = cos x using the auxiliary angle method.

 

[HeroicPandas]

Why are you promoting this website?
You would certainly not want to recommend it as a teaching tool when it solves the equation sin x = cos x using the auxiliary angle method.

lol!