设a=3i-j-2k,b=i+2j-2k 求-3a点乘2b,a×b 和a,b夹角余弦
人气：282 ℃ 时间：2019-10-20 20:10:31
解答
1,若向量a=(a1,b1,c1),向量b=(a2,b2,c2),则 向量a·向量b=a1a2+b1b2+c1c2 即-3a点乘2b=（-9i-3j-6k）·（2i+4j-4k ）=a1a2+b1b2+c1c2 =（-18i-12j+24k）2,向量a×向量b= |a1 b1 c1| |a2 b2 c2| =(b1c2-b2c1,c1a2-a1c...
推荐
- 设a=3i-j-2k,b=i+2j-k,求a与b的夹角余弦
- 设a=3i-j-2k,b=i+2j-k,①求a·b及a*b;②(-2a)·3b及a*b;③a与b的夹角的余弦
- 设a=3i-j-2k,b=i+2j-k,求a与b的夹角余弦{答案是cos（a,b）=3/(2√21）}求步骤
- 设向量a=3i-j+2k,向量b=i+2j+k,计算:(1)(-2a)*(3b) (2)3a*2b
- 已知|a|=4,|b|=3且(3a-b)⊥(a-2b),求a与b夹角的余弦值
- what i mean is that i still love you and i won't cheat on you again 翻译
- （-2009又6分之5）+（-2008又3分之2）+4018+（-1又2分之1 ）
- eddie doesn't like exercising同义句
猜你喜欢
