tan(x+π/4)=3a∴(tanx+tanπ/4)/(1-tanxtanπ/4)=3(tanx+1)/(1-tanx)=3∴tanx+1=3-3tanx∴tanx=1/2sinxcosx=sinxcosx/(sin²x+cos²x)=tanx/(tan²x+1)=2/5