1) ctgx+cosx=1+ctgx*cosx
2) sin^4x+cos^4x=1/2
3) (sinx-cosx)^2=sin2x
4) sin^4x-cos^4x=7/2(sinxcosx)
5) sin^2x-sinxcosx+cosx-sinx=0
2 answers
How about you try first and post your results.
2) sin^4x+cos^4x=1/2
sin^2x*sin^2x+cos^4x=1/2
(1-cos^2x)(1-cos^2x)+cos^4x=1/2
1-cos^2x-cos^2x+2cos^4x=1/2
2cos^4x-2cos^2x+1=1/2
2cos^4x-2cos^2x+1/2=0
x=pi/4+2kpi x2=7pi/4+2kpi
sin^2x*sin^2x+cos^4x=1/2
(1-cos^2x)(1-cos^2x)+cos^4x=1/2
1-cos^2x-cos^2x+2cos^4x=1/2
2cos^4x-2cos^2x+1=1/2
2cos^4x-2cos^2x+1/2=0
x=pi/4+2kpi x2=7pi/4+2kpi
1 answer