Cevaplar

En İyi Cevap!
2013-01-01T17:36:12+02:00

<u,v>=IIuII.IIvII.cosa 
<(3,0),(0,-4)>=3.4.cos a
3.0 + 0.(-4) = 12.cos a
0=12cos a
0=cos a
a=  90

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