please help.....

[lihinii]

2 sin x+ 3 cos x = a , 3 sin x + 2 cos x = b . Find a connection between a and b.

I tried subtracting the two equations and squaring.

(-sin x +cos x)^2 = (a-b) ^2
which gives me
-sin2x = (a-b)^2 . But what now ...

 

[mmm4444bot]

-sin2x = (a-b)^2

Did you make a typographical error above ?

1 - sin(2x) = (a - b)^2

This equation provides a relationship between a and b because it shows that the square of their difference is 1 - sin(2x).

That is only one of many "connections" between a and b. Here's another:

(3b - 2a)/(3a - 2b) = tan(x)

 

[lihinii]

Thanx so much sir for ur help.. but was wondering whether there is an answer independent of x....just a connection between a and b :?

 

[helenani]

I dont understand what this question is asking. "find the ratio by using the reference angles; sine 200^o, cosine -12^o. I tried angle 20 as the reference angle for 200 but my answer came out wrong.

 

[mmm4444bot]

wondering whether there is an answer independent of x ... just a connection between a and b

I'm thinking that it's possible to express a in terms of b for some angles, but such an expression would probably not work for all x.

I'l play with that idea, later today. If I come up with anything interesting, I'll post it.

 

[mmm4444bot]

I dont understand what this question is asking. "find the ratio by using the reference angles; sine 200^o, cosine -12^o

This exercise asks for the value of sin(200°) and cos(-12°). Specifically, the exercise wants you to use the reference angle for each, to determine the value.



I tried angle 20 as the reference angle for 200

That's very good. When you used this reference angle, what did you get ?

I can't see your work, so I don't know what you're doing.

Also, I don't know what material your class has covered, so far.

:?: Is your class using calculators to evaluate ratios like sin(20°) ?

:?: What is the reference angle for cos(-12°) ?

:?: Do you know in which Quadrant the terminal ray of angles 200° and -12° lie ?

:?: Have you memorized the signs of the trig ratios sine and cosine, for each Quadrant ?

All of this information is important. Please answer my questions, and we'll go from there.

PS: Please use the [NEWTOPIC] button on the boards' index page, to start your own thread for each new exercise.

 

[helenani]

The Acme plumbing company will send a team of 3 plumbers to work on a certain job. The company has 4 experienced workers and 4 trainees. If a team consists of 1 experienced plumber and 2 trainees, how many different such teams are possible?

 

[Denis]

You were already told to use "NEWTOPIC" button, to start a new thread. PLEASE DO SO.