◆数学◆向量a=(2,2),向量b与向量a的夹角为3π/4,且a·b=-2(1)求向量b;(2)若向量t=(1,0),且b⊥t,向量c=(cosA,2cos^2(C/2)),其中A,C是△ABC的内角,若三角形的三内角A,B,C依次成等差数列,试求│b+c│
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![◆数学◆向量a=(2,2),向量b与向量a的夹角为3π/4,且a·b=-2(1)求向量b;(2)若向量t=(1,0),且b⊥t,向量c=(cosA,2cos^2(C/2)),其中A,C是△ABC的内角,若三角形的三内角A,B,C依次成等差数列,试求│b+c│](/uploads/image/z/6903798-6-8.jpg?t=%E2%97%86%E6%95%B0%E5%AD%A6%E2%97%86%E5%90%91%E9%87%8Fa%3D%282%2C2%29%2C%E5%90%91%E9%87%8Fb%E4%B8%8E%E5%90%91%E9%87%8Fa%E7%9A%84%E5%A4%B9%E8%A7%92%E4%B8%BA3%CF%80%2F4%2C%E4%B8%94a%C2%B7b%3D-2%EF%BC%881%EF%BC%89%E6%B1%82%E5%90%91%E9%87%8Fb%3B%EF%BC%882%EF%BC%89%E8%8B%A5%E5%90%91%E9%87%8Ft%3D%EF%BC%881%2C0%EF%BC%89%2C%E4%B8%94b%E2%8A%A5t%2C%E5%90%91%E9%87%8Fc%3D%EF%BC%88cosA%2C2cos%5E2%28C%2F2%29%29%2C%E5%85%B6%E4%B8%ADA%2CC%E6%98%AF%E2%96%B3ABC%E7%9A%84%E5%86%85%E8%A7%92%2C%E8%8B%A5%E4%B8%89%E8%A7%92%E5%BD%A2%E7%9A%84%E4%B8%89%E5%86%85%E8%A7%92A%2CB%2CC%E4%BE%9D%E6%AC%A1%E6%88%90%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%2C%E8%AF%95%E6%B1%82%E2%94%82b%2Bc%E2%94%82)
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