已知:m+1/m=5,则m²+1/m²= ,m3+1/m3=
问题描述:
已知:m+1/m=5,则m²+1/m²= ,m3+1/m3=
答
∵m+1/m=5
∴m²+1/m²
=(m+1/m)²-2
=25-2
=23
∴m³+1/m³
=(m+1/m)(m²+1/m²-1)
=5×(23-1)
=5×22
=110