Saturday, 5 July 2014

algebra precalculus - Solve cosx+8sinx7=0




Solve cosx+8sinx7=0





My attempt:



8sinx=7cosx8(2sinx2cosx2)=7cosx16sinx2cosx2=71+2sin2x216sinx2cosx2=6+2sin2x28sinx2cosx2=3+sin2x20=sin2x28sinx2cosx2+30=sinx2(sinx28cosx2)+3



I'm not sure how to proceed from here (if this process is even right at all?) . Any help would be appreciated. Thanks.


Answer



Divide either sides by cos2x2 sin2x28sinx2cosx2+3=0 to get tan2x28tanx2+3(1+tan2x2)=0 which on rearrangement is a Quadratic Equation in tanx2


No comments:

Post a Comment

real analysis - How to find limhrightarrow0fracsin(ha)h

How to find lim without lhopital rule? I know when I use lhopital I easy get $$ \lim_{h\rightarrow 0}...