设全集U=R,M={m/方程mx2-x-1=0有实数根},N={n/方程x2-x+n=0有实数根}求(CuM)nN.

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设全集U=R,M={m/方程mx2-x-1=0有实数根},N={n/方程x2-x+n=0有实数根}求(CuM)nN.

设全集U=R,M={m/方程mx2-x-1=0有实数根},N={n/方程x2-x+n=0有实数根}求(CuM)nN.
设全集U=R,M={m/方程mx2-x-1=0有实数根},N={n/方程x2-x+n=0有实数根}求(CuM)nN.

设全集U=R,M={m/方程mx2-x-1=0有实数根},N={n/方程x2-x+n=0有实数根}求(CuM)nN.
m=0,-x-1=0有实根
m≠0,1+4m≥0,m≥-1/4且m≠0
所以m≥-1/4
N则判别式1-4n≥0
n≤1/4
所以CuM是m