Let A=xyzyzxzxy, where x,y andz are real numbers such that x+y+z>0 and xyz=2 . If A2=I3, then the value of x3+y3+z3 is_________.
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answer is 7.
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Detailed Solution
Given A2=xyzyzxzxyxyzyzxzxy=100010001it gives x2+y2+z2=1; xy+yz+zx=0Consider the determinantsA2=I=1⇒A=-1A=3xyz−x3−y3−z3 =−x+y+zx2+y2+z2−xy−yz−zx6−x3+y3+z3=−1x3+y3+z3=7 Therefore, x3+y3+z3=7