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標題:

A maths Question

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• 我完全5明中二d數,可以點-@1@
• +s +a 喱d符號點解-@1@
• 我的電腦雙擊 C-- 後不能到 C-- 內

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Given that √a=0.3 and √b=0.4, Evaluate √a+b.

最佳解答:

Given √a = 0.3 and √b = 0.4 Consider (a + b) = [√(a + b)]2 And (a + b) = (√a)2 + 2√a√b + (√b)2 = (0.3)2 + 2(0.3)(0.4) + (0.4)2 = 0.49 So, √(a + b) = √0.49 = 0.7

其他解答:

a^2+b^2 not = to ( a+b)^2 in this qu., we may let √A be a ,a be a^2 , to proof this answer is wrong. The correct answer is √((a+b)-2√a√b) a+b=(√a)^2+2√a√b+(√b)^2 - 2√a√b =0.49-0.24 =0.25 so √(a+b)=0.5