
equation with inverse trig fcn???HELP
Posted:
Apr 6, 1998 6:01 PM


Given the equation : arcsin(3xpi)=1/2
I solved it by taking the "sin" of both sides yielding the solution of 3xpi = sin 1/2 so x= (pi +sin 1/2)(3) or approximately 1.207006064...
One of my students solved this equation by saying: Let u= 3xpi
then arcsin(u) =1/2
then u= pi/6
so 3xpi =pi/6 resulting in x = (pi +pi/6)/3 approximately equal to 1.22173...
Why are these solutions not equal??? I assume I am missing something.
Karol Gray East Surry HS Pilot Mountain, NC

