Posted by Anonymous on .
Simplify #3:
[cosxsin(90x)sinx]/[cosxcos(180x)tanx]
= [cosx(sin90cosxcos90sinx)sinx]/[cosx(cos180cosx+sinx180sinx)tanx]
= [cosx((1)cosx(0)sinx)sinx]/[cosx((1)cosx+(0)sinx)tanx]
= [cosxcosxsinx]/[cosx+cosxtanx]
= [cosx(1sinx]/[cosx(1+tanx]
= (1sinx)/(1+tanx)
Is this correct???

Trigonometry Check 
Steve,
looks good to me