Re: Solving a simple equation
- To: mathgroup at smc.vnet.net
- Subject: [mg121876] Re: Solving a simple equation
- From: "Dr. Wolfgang Hintze" <weh at snafu.de>
- Date: Wed, 5 Oct 2011 04:04:14 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <j6e675$kds$1@smc.vnet.net>
"Daniel Kallfaß" <eizdealer at web.de> schrieb im Newsbeitrag news:j6e675$kds$1 at smc.vnet.net... > Hi there, I wonder why the following equation cannot be solved: > > \[Kappa] = 1.4 > \[CapitalTheta] = 10; > NSolve[Tan[\[Theta] degree] == > 2*Cot[\[Beta] degree]*(ma1^2*Sin[\[Beta] degree]^2 - 1)/( > ma1^2*(\[Kappa] + Cos[2 \[Beta] degree]) + 2), \[Beta]] > > It says: NSolve::nsmet: This system cannot be solved with the methods > available to NSolve. > > Is there something I'm missing? My Voyage 200 solves it without any > issues. > > Thanks, > Daniel > The constant ma1 has no values assigned. If you set it (e.g. to 5) you'll get pretty normal solutions (see below). PS: I changed angles to radians, hence Beta must be multiplied by 180/Pi to get it in degrees. Wolfgang \[Kappa] = 1.4 \[Theta] = 10*(Pi/180); ma1 = 5; NSolve[Tan[\[Theta]] == 2*Cot[\[Beta]]*((ma1^2*Sin[\[Beta]]^2 - 1)/(ma1^2*(\[Kappa] + Cos[2*\[Beta]]) + 2)), \[Beta]] 1.4 Solve::"ifun"\), ":", "\<\"Inverse functions are being used by (Solve), so some solutions may not be found; use Reduce for complete solution information. {{\[Beta] -> -2.8034174741802227}, {\[Beta] -> -1.615304107903905}, {\[Beta] -> -0.11913447310112904}, {\[Beta] -> 0.33817517940957037}, {\[Beta] -> 1.5262885456858881}, {\[Beta] -> 3.0224581804886643}}