log2为底数根号7/48为真数+log2为底数12为真数-1/2log2为底数42为真数=?
问题描述:
log2为底数根号7/48为真数+log2为底数12为真数-1/2log2为底数42为真数=?
答
=log2[√(7/48)]+log2(12)-log2(√42)
=log2[√(7/48)*12÷√42]
=log2[√(1/2)]
=log2[2^(-1/2)]
=-1/2