Verifying Solutions for Differential Equations Practice Test

No, because $y'=\tan^2 x$ but $1+y^2=\sec^2 x$.

No, because $y'=\sec^2 x$ but $1+y^2=1+\sec^2 x$.

Yes, because $y'=\sec^2 x$ and $1+y^2=\csc^2 x$.

No, because $y'=\sec x$ but $1+y^2=\sec^2 x$.

Yes, because $y'=\sec^2 x$ and $1+\tan^2 x=\sec^2 x$.