SEARCH HOME
Math CentralQuandaries & Queries

search

Question from James, a student:

I need to prove trig identities, and I can't figure this one out

1 + sinx - cosx        1 - cosx
-------------------- = -------------
1 + sinx + cosx          sinx

James,

Try cross-multiplying -- that is, multiply both sides of the identity by (sin x)(1 + sin x + cos x). If the modified identity holds for all x (except where multiplying by 0), then so does the original.

Chris

About Math Central
 

 


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.
Quandaries & Queries page Home page University of Regina PIMS