∵sin(π+α)=-3/5
∴-sinα = -3/5
∴sinα = 3/5
∵α是第二象限
∴cosα = -√(1-sin^2α) = -√(1-(3/5)^2) = -4/5
sin2α = 2sinαcosα = 2*3/5*(-4/5) = -24/25
cos2α = 1-2sin^2α = 1 - 2*(3/5)^2 = 7/25
tan2α = sin2α/cos2α = (24/5)/(7/25) = -24/7
∵sin(π+α)=-3/5
∴-sinα = -3/5
∴sinα = 3/5
∵α是第二象限
∴cosα = -√(1-sin^2α) = -√(1-(3/5)^2) = -4/5
sin2α = 2sinαcosα = 2*3/5*(-4/5) = -24/25
cos2α = 1-2sin^2α = 1 - 2*(3/5)^2 = 7/25
tan2α = sin2α/cos2α = (24/5)/(7/25) = -24/7