Posted by LiNnda on Thursday, May 6, 2010 at 8:02am.
1) ctgx+cosx=1+ctgx*cosx
2) sin^4x+cos^4x=1/2
3) (sinxcosx)^2=sin2x
4) sin^4xcos^4x=7/2(sinxcosx)
5) sin^2xsinxcosx+cosxsinx=0

Not doing all those, already know how  Damon, Thursday, May 6, 2010 at 8:18am
How about you try first and post your results.

equations trig  LiNnda, Thursday, May 6, 2010 at 8:51am
2) sin^4x+cos^4x=1/2
sin^2x*sin^2x+cos^4x=1/2
(1cos^2x)(1cos^2x)+cos^4x=1/2
1cos^2xcos^2x+2cos^4x=1/2
2cos^4x2cos^2x+1=1/2
2cos^4x2cos^2x+1/2=0
x=pi/4+2kpi x2=7pi/4+2kpi
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