Centrale des maths - centraledesmaths.uregina.ca
Dilemmes & doutes
« D & D »
 Sujet: cos^-1
nouvelle recherche

Un article trouvé pour ce sujet.

 Page1/1
 Using the inverse sine function 2000-05-31 Nelson Rothermel pose la question :This has me completely baffled. I have to use the laws of sine or cosine to find the angles of a triangle when I have 3 sides, so I can't go 180-x-y when I have 2 angles. Now, I have a triangle with values of 3, 7, and 9. Here are the steps I used (A,B,C are angles; a,b,c are opposite sides): angle A (16.1951 degrees): cos-1*((b2+c2-a2)/(2*b*c)) angle B (40.6011 degrees): sin-1*(b*sin(A)/a) angle C (56.7962 degrees): sin-1*(c*sin(A)/a) If you notice, A+B+C does not equal 180. According to the book, A and B are correct, but C is supposed to be 123.2038 degrees. Why doesn't it work??? Harley Weston lui répond.

 Page1/1

 Centrale des maths reçoit une aide financière de l’Université de Regina et de The Pacific Institute for the Mathematical Sciences.
 Qui sommes-nous :: carte du site :: our english site