已知i的模=j的模=1,且i向量⊥j向量,a向量=-3j向量+2j向量,b向量=i向量+4j向量,则(a向量+b向量)乘以(a向量-b向量)=?求讲解诶
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![已知i的模=j的模=1,且i向量⊥j向量,a向量=-3j向量+2j向量,b向量=i向量+4j向量,则(a向量+b向量)乘以(a向量-b向量)=?求讲解诶](/uploads/image/z/8552291-59-1.jpg?t=%E5%B7%B2%E7%9F%A5i%E7%9A%84%E6%A8%A1%3Dj%E7%9A%84%E6%A8%A1%3D1%2C%E4%B8%94i%E5%90%91%E9%87%8F%E2%8A%A5j%E5%90%91%E9%87%8F%2Ca%E5%90%91%E9%87%8F%3D-3j%E5%90%91%E9%87%8F%2B2j%E5%90%91%E9%87%8F%2Cb%E5%90%91%E9%87%8F%3Di%E5%90%91%E9%87%8F%2B4j%E5%90%91%E9%87%8F%2C%E5%88%99%28a%E5%90%91%E9%87%8F%2Bb%E5%90%91%E9%87%8F%29%E4%B9%98%E4%BB%A5%EF%BC%88a%E5%90%91%E9%87%8F-b%E5%90%91%E9%87%8F%EF%BC%89%3D%3F%E6%B1%82%E8%AE%B2%E8%A7%A3%E8%AF%B6)
已知i的模=j的模=1,且i向量⊥j向量,a向量=-3j向量+2j向量,b向量=i向量+4j向量,则(a向量+b向量)乘以(a向量-b向量)=?求讲解诶
已知i的模=j的模=1,且i向量⊥j向量,a向量=-3j向量+2j向量,b向量=i向量+4j向量,则(a向量+b向量)乘以
(a向量-b向量)=?求讲解诶
已知i的模=j的模=1,且i向量⊥j向量,a向量=-3j向量+2j向量,b向量=i向量+4j向量,则(a向量+b向量)乘以(a向量-b向量)=?求讲解诶
题目似乎应为a=-3i+2j,a^2=13,b^2=17,
向量(a+b)(a-b)=a^2-b^2=13-17=-4.