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In trangle ABC a4+b4+c4-2c2(a2+b2)=0 proove c=45 or135 |
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Answer» Given condition can be written as a^4+b^4+c^4-2c^2(a^2+b^2)+2a^2b^2=2a^2b^2 =>[(a^2+b^2-c^2)/(2ab)]^2==1/2 =>cos^2C=1/2 =>cosC=+1/√2 or -1/√2 Then C= 45° or135° |
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