qns!!!

• jay_rocks

  6 Feb 06, 14:46

  (tan x + sin x) ( tan x - sin x) = tan² x sin² x
  
  i got my ans as tan^2 x - sin^2 x
• yuko-ogura

  6 Feb 06, 14:57

  Originally posted by jay_rocks:

  (tan x + sin x) ( tan x - sin x) = tan² x sin² x
  
  i got my ans as tan^2 x - sin^2 x

  start from RHS..
  
  RHS=tan^2 x sin^2 x
  = (sec^2 x - 1) (sin^2 x)
  = (1/(cos^2 x) - 1) (sin^2 x)
  = (tan^2 x - sin^2 x)
  = (tan x + sin x) (tan x - sin x)
  = LHS
• jay_rocks

  6 Feb 06, 15:03

  Originally posted by yuko-ogura:

  start from RHS..
  
  RHS=tan^2 x sin^2 x
  = (sec^2 x - 1) (sin^2 x)
  = (1/(cos^2 x) - 1) (sin^2 x)
  = (tan^2 x - sin^2 x)
  = (tan x + sin x) (tan x - sin x)
  = LHS

  yuan lai my one oso can further do one...
• yuko-ogura

  6 Feb 06, 15:05

  Originally posted by jay_rocks:

  yuan lai my one oso can further do one...

  yuan lai ur maths hw is like that do one...
• jay_rocks

  6 Feb 06, 15:10

  Originally posted by yuko-ogura:

  yuan lai ur maths hw is like that do one...

  u do frm RHS. i do frm LHS oso can. heh.
• yuko-ogura

  6 Feb 06, 15:13

  Originally posted by jay_rocks:

  u do frm RHS. i do frm LHS oso can. heh.

  no la..wad i meant..was dat yuan lai ur maths hw is done by the forumites one.
  
  jia you ba..jc life quite fun.
• jay_rocks

  6 Feb 06, 15:17

  Originally posted by yuko-ogura:

  no la..wad i meant..was dat yuan lai ur maths hw is done by the forumites one.
  
  jia you ba..jc life quite fun.

  oh...did i say i nw studying in jc ?
• yuko-ogura

  6 Feb 06, 15:18

  Originally posted by jay_rocks:

  oh...did i say i nw studying in jc ?

  sec 4 stuff then?cux the first three mths in jc also study wad ur asking now.
• jay_rocks

  6 Feb 06, 15:21

  Originally posted by yuko-ogura:

  sec 4 stuff then?cux the first three mths in jc also study wad ur asking now.

  (cosec x -1) (cosec x + 1) ( sec x -1) ( sec x + 1) = 1
• CoolMyth

  6 Feb 06, 15:30

  Originally posted by jay_rocks:

  (cosec x -1) (cosec x + 1) ( sec x -1) ( sec x + 1) = 1

  Using (a - b)(a + b) = a^2 - b^2
  
  (cosec x -1) (cosec x + 1) ( sec x -1) ( sec x + 1) = 1
  
  LHS
  = (cosec x -1) (cosec x + 1) ( sec x -1) ( sec x + 1)
  = (cosec^2 x -1)(sec^2 x -1)
  = (cot^2 x)(tan^2 x)
  = 1
  = RHS
  
  
• jay_rocks

  6 Feb 06, 15:32

  Originally posted by jay_rocks:

  (cosec x -1) (cosec x + 1) ( sec x -1) ( sec x + 1) = 1

  solved
• yuko-ogura

  6 Feb 06, 15:35

  Originally posted by jay_rocks:

  solved

  congrats.
• papercut87

  6 Feb 06, 17:28

  i think jay_rocks is a sec 4 students mugging for Os this yr.. haha.
• ndmmxiaomayi

  10 Feb 06, 15:42

  Originally posted by jay_rocks:

  oh...did i say i nw studying in jc ?

  I did all this in secondary school. Nowadays, kids so good. Do in JC.
• mystiv

  13 Feb 06, 00:39

  Originally posted by ndmmxiaomayi:

  I did all this in secondary school. Nowadays, kids so good. Do in JC.

  i do that in sec 3