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Topic: UPDATE: inverse trig equation (help)
Replies: 1   Last Post: Apr 8, 1998 11:50 AM

 Messages: [ Previous | Next ]
 kgray@InfoAve.Net Posts: 54 Registered: 12/6/04
UPDATE: inverse trig equation (help)
Posted: Apr 7, 1998 2:31 PM

After giving this solution further consideration I realized the error in
the 2nd solution. (Translated incorrectly) Thanks to all who may have
corresponded!

Given the equation : arcsin(3x-pi)=1/2

I solved it by taking the "sin" of both sides yielding the solution of
3x-pi = 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= 3x-pi

then arcsin(u) =1/2

then u= pi/6

so 3x-pi =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

Date Subject Author
4/7/98 kgray@InfoAve.Net
4/8/98 D Mitchell