how SIN, COS and TAN works on sql server
in [Programming SQL]
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From: Roy Goldhammer on 24 May 2010 09:36 I ran this: declare @f float set @f = 30 select sin(@f) and got -0.988031624092862 What is this?
From: Dan on 24 May 2010 10:08 "Roy Goldhammer" <royg(a)yahoo.com> wrote in message news:eRKvnY0#KHA.5476(a)TK2MSFTNGP06.phx.gbl... > I ran this: > > declare @f float > > set @f = 30 > > select sin(@f) > > and got -0.988031624092862 > > What is this? > > The values for SIN, COS, and TAN are in radians, not degrees. You are seeing the value of SIN(30 radians), which is correct. -- Dan
From: Dan on 24 May 2010 10:14 "Dan" <news(a)worldofspack.com> wrote in message news:uw5$kq0#KHA.3176(a)TK2MSFTNGP05.phx.gbl... > > "Roy Goldhammer" <royg(a)yahoo.com> wrote in message > news:eRKvnY0#KHA.5476(a)TK2MSFTNGP06.phx.gbl... >> I ran this: >> >> declare @f float >> >> set @f = 30 >> >> select sin(@f) >> >> and got -0.988031624092862 >> >> What is this? >> >> > > The values for SIN, COS, and TAN are in radians, not degrees. You are > seeing the value of SIN(30 radians), which is correct. > Forgot to mention that this should give you what you're expecting: declare @f float --converts degrees to radians set @f = radians(@f) select sin(@f) which is 0.499999 (recurrring), and that is the float version of 0.5. Cast the result to a decimal and it'll round out to 0.5 -- Dan
From: Dan on 24 May 2010 10:17 "Dan" <news(a)worldofspack.com> wrote in message news:uQrhzt0#KHA.3972(a)TK2MSFTNGP02.phx.gbl... > > "Dan" <news(a)worldofspack.com> wrote in message > news:uw5$kq0#KHA.3176(a)TK2MSFTNGP05.phx.gbl... >> >> "Roy Goldhammer" <royg(a)yahoo.com> wrote in message >> news:eRKvnY0#KHA.5476(a)TK2MSFTNGP06.phx.gbl... >>> I ran this: >>> >>> declare @f float >>> >>> set @f = 30 >>> >>> select sin(@f) >>> >>> and got -0.988031624092862 >>> >>> What is this? >>> >>> >> >> The values for SIN, COS, and TAN are in radians, not degrees. You are >> seeing the value of SIN(30 radians), which is correct. >> > > Forgot to mention that this should give you what you're expecting: > > > declare @f float > > --converts degrees to radians > set @f = radians(@f) > > select sin(@f) > > > which is 0.499999 (recurrring), and that is the float version of 0.5. Cast > the result to a decimal and it'll round out to 0.5 > Gah, having one of those days today. Here's the working code: declare @f float set @f = 30 --converts degrees to radians set @f = radians(@f) select sin(@f) -- Dan
From: Erland Sommarskog on 24 May 2010 10:16 Roy Goldhammer (royg(a)yahoo.com) writes: > I ran this: > > declare @f float > > set @f = 30 > > select sin(@f) > > and got -0.988031624092862 > > What is this? The sinus value of 30 radians. If you intended 30 degrees try: select sin(radians(30E0)) (Using only "30" does not work, as the return type of radians() is the same as the input type - quite silly if you ask me.) At least you are not alone. The topic for SIN in Books Online says: Returns the trigonometric sine of the specified angle, in radians So far, so good, but then there is the example: DECLARE @angle float SET @angle = 45.175643 SELECT 'The SIN of the angle is: ' + CONVERT(varchar,SIN(@angle)) GO -- Erland Sommarskog, SQL Server MVP, esquel(a)sommarskog.se Books Online for SQL Server 2005 at http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx Books Online for SQL Server 2000 at http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx
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