# math writing trignometric expressions in the form Rsin(thetha+alpha) confusion

Announcements
#1
as title says, suppose you had the expression cos(thetha)+(sqrt3)sin(thetha), how would you know whether you write it in the form Rcos(thetha-alpha) or Rsin(thetha+alpha).. I really don't see why there should be a difference, though when I used Rcos(thetha-alpha) for this particular expression instead of Rsin(thetha+alpha), when solving for costheta+(sqrt3)sinthetha =2.. the answer came out wrong according to ms.
0
1 month ago
#2
R will.obviously be the same whichever way you do it.

As for choice, unless the question specifies which, there shouldn't be any real difference, especially since the done and cosine curves are a pi/2 translation away from.each other.

Might be wise for you to post piccies of the question, your working and perhaps the MS.

I assume you've got your calculator in the correct angle mode? Has been known
Last edited by T!gger34; 1 month ago
0
1 month ago
#3
(Original post by Abraham_Otaku)
as title says, suppose you had the expression cos(thetha)+(sqrt3)sin(thetha), how would you know whether you write it in the form Rcos(thetha-alpha) or Rsin(thetha+alpha).. I really don't see why there should be a difference, though when I used Rcos(thetha-alpha) for this particular expression instead of Rsin(thetha+alpha), when solving for costheta+(sqrt3)sinthetha =2.. the answer came out wrong according to ms.
0
X

new posts
Back
to top
Latest

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### Poll

Join the discussion

Talking to current university students (12)
17.65%
Talking to peers going through the same thing (24)
35.29%
Speaking to student ambassadors from the universities (5)
7.35%
Speaking to staff members from universities (1)
1.47%
Using the personal statement builder, library or helper service (7)
10.29%
20.59%
Learning about/speaking to Student Finance England (2)
2.94%
Something else (tell us in the thread) (3)
4.41%