i cannot seem to even start this question off and it is really bugging me. I know i have to put in a double angle formula somewhere but i just don't know where or when!
Any help would be great! thank you
0
2002 Winter Diet, paper 2, Q5
Started by x_Jo_x, May 02 2007 08:07 PM
3 replies to this topic
#2
-
- Members
-
- 384 posts
Top of the Class
- Location:Newmilns/Kilmarnock
- Gender:Male
Posted 02 May 2007 - 08:59 PM
Well, if you look at your formulae list, you'll see that 
, so:
It is relatively easy to solve from there, but post if you have any problems
Just remember that it's for 
, so you should end up with four different values.
, so:It is relatively easy to solve from there, but post if you have any problems
Just remember that it's for , so you should end up with four different values.
#3
-
- Members
-
- 62 posts
Good Effort
- Location:Port Glasgow
- Gender:Female
Posted 02 May 2007 - 09:06 PM
Hey, im not 100% sure if i did this right, but i got the same answer as thepast paper book.
cos2x - 2sin²x = 0
cos²x - sin²x - 2sin²x = 0
cos²x = sin²x - 2sin²x
cos²x = sinx²(1-2)
cos²x = 1 over 2
cos2x = 1 over 2
cos2x = 60°
cos2x = pie over 6, 5pie over 3
cosx = pie over 6, 5 pie over 6, 7 pie over 6, 11pie over 6
^^^hoped that helped a wee bit
cos2x - 2sin²x = 0
cos²x - sin²x - 2sin²x = 0
cos²x = sin²x - 2sin²x
cos²x = sinx²(1-2)
cos²x = 1 over 2
cos2x = 1 over 2
cos2x = 60°
cos2x = pie over 6, 5pie over 3
cosx = pie over 6, 5 pie over 6, 7 pie over 6, 11pie over 6
^^^hoped that helped a wee bit
#4
-
- Members
-
- 76 posts
Good Effort
- Gender:Female
Posted 03 May 2007 - 09:18 PM
hey, thanks guys,, that has really helped. The help was very much appreciated!
1 user(s) are reading this topic
0 members, 1 guests, 0 anonymous users
