二次根式的加减
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1.(x√y-y√x)/(x√y+y√x)-(y√x+x√y)/(y√x-x√y)
=√xy(√x-√y)/√xy(√x+√y)-√xy(√y+√x)/√xy(√y-√x)
=(√x-√y)/(√x+√y)-(√y+√x)/(√y-√x)
=(√x-√y)/(√x+√y)+(√x+√y)/(√x-√y)
=[(√x-√y)²+(√x+√y)²]/(√x+√y)*(√x-√y)
=(2x+2y)/(x-y)
2.(a+2√ab+b)/(a-b)-[√a/(a+√ab)-√b/(b-√ab)]/√a/(b+√ab)
=(a+2√ab+b)/(a-b)-[√a/√a(√a+√b)-√b/√b(√b-√a)]*(b+√ab)/√a
=(a+2√ab+b)/(a-b)-[1/(√a+√b)-1/(√b-√a)]*(b+√ab)/√a
=(a+2√ab+b)/(a-b)-[1/(√a+√b)+1/(√a-√b)]*(b+√ab)/√a
=(a+2√ab+b)/(a-b)-[(√a+√b)+(√a-√b)/(√a+√b)(√a-√b)]*(b+√ab)/√a
=(a+2√ab+b)/(a-b)-2(b+√ab)/(√a+√b)(√a-√b)
=(a+2√ab+b)/(a-b)-(2√ab+2b)/(a-b)
=(a-b)/(a-b)
=1
=√xy(√x-√y)/√xy(√x+√y)-√xy(√y+√x)/√xy(√y-√x)
=(√x-√y)/(√x+√y)-(√y+√x)/(√y-√x)
=(√x-√y)/(√x+√y)+(√x+√y)/(√x-√y)
=[(√x-√y)²+(√x+√y)²]/(√x+√y)*(√x-√y)
=(2x+2y)/(x-y)
2.(a+2√ab+b)/(a-b)-[√a/(a+√ab)-√b/(b-√ab)]/√a/(b+√ab)
=(a+2√ab+b)/(a-b)-[√a/√a(√a+√b)-√b/√b(√b-√a)]*(b+√ab)/√a
=(a+2√ab+b)/(a-b)-[1/(√a+√b)-1/(√b-√a)]*(b+√ab)/√a
=(a+2√ab+b)/(a-b)-[1/(√a+√b)+1/(√a-√b)]*(b+√ab)/√a
=(a+2√ab+b)/(a-b)-[(√a+√b)+(√a-√b)/(√a+√b)(√a-√b)]*(b+√ab)/√a
=(a+2√ab+b)/(a-b)-2(b+√ab)/(√a+√b)(√a-√b)
=(a+2√ab+b)/(a-b)-(2√ab+2b)/(a-b)
=(a-b)/(a-b)
=1
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