feustel@netcom.COM (David Feustel) (04/24/91)
Entering .36 and selecting units gold degrees results in a conversion to 119 degrees. Entering .36_R and selecting units gold degrees results in 20 degrees. The calculator is in RAD mode thruout. Is this an error? If not, why don't I get the same conversion in both cases? -- David Feustel, 1930 Curdes Ave, Fort Wayne, IN 46805, (219) 482-9631 EMAIL: netcom.com
louxj@jacobs.CS.ORST.EDU (John W. Loux) (04/25/91)
In article <1991Apr24.034152.29237@netcom.COM> feustel@netcom.COM (David Feustel) writes: >Entering .36 and selecting units gold degrees results in a conversion >to 119 degrees. Entering .36_R and selecting units gold degrees >results in 20 degrees. The calculator is in RAD mode thruout. Is this >an error? If not, why don't I get the same conversion in both cases? >-- >David Feustel, 1930 Curdes Ave, Fort Wayne, IN 46805, (219) 482-9631 >EMAIL: netcom.com I don't remember where I read this, and I can't find it in the manuals (doesn't mean it's not there), but a little experimentation verifies that: In terms of angular measure, a real number is considered to be a number of cycles (i.e., multiples of 2\pi) and is considered so regardless of angle mode. Converting the real number 1 to degrees, radians and grads returns 360_\^o, 6.28318530718_r, and 400_grad, respectively, each of which is one cycle in its respective units. Unfortunately, when I perform the calculations you describe above, I get 129.6_\^o and 20.6264806247_\^o which differ from your values (but I am hoping yours are typing/rounding errors). John W. Loux Solve and Integrate Corp. louxj@jacobs.cs.orst.edu john@solvint.UUCP
rsholmes@rodan.acs.syr.edu (Rich Holmes) (04/25/91)
In article <1991Apr24.034152.29237@netcom.COM> feustel@netcom.COM (David Feustel) writes: >Entering .36 and selecting units gold degrees results in a conversion >to 119 degrees. Entering .36_R and selecting units gold degrees >results in 20 degrees. The calculator is in RAD mode thruout. Is this >an error? If not, why don't I get the same conversion in both cases? Hmm. Interesting. I don't see this in the manual. When converting units, a number without units is considered to be fractions of a full circle. Example: with either radians or degrees mode set, do 1 gold degrees; you get 360_deg. However, for trig functions, a number without units is taken to be radians or degrees, depending on what mode is set. This may be a feature, not a bug, but it is a tad confusing. It also means if you are in degrees mode and take the ASIN of a 0.5, getting 30 (degrees), and then you say, oh bugger, I wanted that in radians, and you press gold R, you get 188.495559215_r. Seems like the natural thing to do, but it gives you the wrong answer. Instead, you must multiply the 30 by 1_deg before converting. -- - Rich Holmes rich@suhep.bitnet or rich@suhep.phy.syr.edu Syracuse U. Physics Dept. or if you must: rsholmes@rodan.acs.syr.edu The Kuwaitis have oil. The Kurds don't. End of story.