  Math Central - mathcentral.uregina.ca  Quandaries & Queries    Q & Q    Topic: sin^-1   start over

2 items are filed under this topic.    Page1/1            sin x = -0.25 2011-03-29 From Wayne:How do you solve for x in the equation sin x = -0.25 the answer is 3.394 and 6.030 but I don't know the steps they used to calculate thisAnswered by Penny Nom.     Using the inverse sine function 2000-05-31 From Nelson Rothermel: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??? Answered by Harley Weston.      Page1/1    Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.    about math central :: site map :: links :: notre site français