若a,b,c∈R,且∣a-c∣<∣b∣,则有( )A,∣a∣>∣b∣+∣c∣B, ∣a∣<∣b∣-∣c∣C,∣a∣<∣b∣+∣c∣D,∣a∣>∣c∣-∣b∣单选,请附讲解~
热心网友
因为 |a| - |c| ≤ | a - c |而本题又有 | a - c | < |b|所以 |a| - |c| < |b| 所以 |a| < |b| + |c|
热心网友
|a|-|b|≤|a±b|≤|a|+|b||a|-|c|≤∣a-c∣<|b|∴C,∣a∣<∣b∣+∣c∣
若a,b,c∈R,且∣a-c∣<∣b∣,则有( )A,∣a∣>∣b∣+∣c∣B, ∣a∣<∣b∣-∣c∣C,∣a∣<∣b∣+∣c∣D,∣a∣>∣c∣-∣b∣单选,请附讲解~
因为 |a| - |c| ≤ | a - c |而本题又有 | a - c | < |b|所以 |a| - |c| < |b| 所以 |a| < |b| + |c|
|a|-|b|≤|a±b|≤|a|+|b||a|-|c|≤∣a-c∣<|b|∴C,∣a∣<∣b∣+∣c∣