Question 1121304
{{{-4 cos x =-sin^2(x)+4}}}


{{{-4cos(x)=-sin^2(x)+4}}}

{{{-4cos(x)=cos^2(x)-1+4}}}

{{{cos^2(x)+4cos(x)+3=0}}}

{{{(cos(x)+1)(cos(x)+3)=0}}}

{{{cos(x)=-1}}}


{{{x=pi}}}

(Check for mistakes)









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sin^2(x)+cos^2(x)=1
sin^2(x)=1-cos^2(x)