1、计算:①(2+1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)②(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^152、①当3的x次方=2时,求(1/9)²-1的值②已知x-y=1,求x²-y²+3x-5y
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![1、计算:①(2+1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)②(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^152、①当3的x次方=2时,求(1/9)²-1的值②已知x-y=1,求x²-y²+3x-5y](/uploads/image/z/1856182-22-2.jpg?t=1%E3%80%81%E8%AE%A1%E7%AE%97%EF%BC%9A%E2%91%A0%EF%BC%882%2B1%EF%BC%89%EF%BC%882%26%23178%3B%2B1%EF%BC%89%EF%BC%882%5E4%2B1%EF%BC%89%EF%BC%882%5E8%2B1%EF%BC%89%E2%80%A6%282%5E2048%2B1%29%E2%91%A1%EF%BC%881%2B1%2F2%EF%BC%89%EF%BC%881%2B1%2F2%5E2%EF%BC%89%EF%BC%881%2B1%2F2%5E4%EF%BC%89%EF%BC%881%2B1%2F2%5E8%EF%BC%89%2B1%2F2%5E152%E3%80%81%E2%91%A0%E5%BD%933%E7%9A%84x%E6%AC%A1%E6%96%B9%3D2%E6%97%B6%2C%E6%B1%82%EF%BC%881%2F9%EF%BC%89%26%23178%3B-1%E7%9A%84%E5%80%BC%E2%91%A1%E5%B7%B2%E7%9F%A5x-y%3D1%2C%E6%B1%82x%26%23178%3B-y%26%23178%3B%2B3x-5y)
1、计算:①(2+1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)②(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^152、①当3的x次方=2时,求(1/9)²-1的值②已知x-y=1,求x²-y²+3x-5y
1、计算:①(2+1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)
②(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^15
2、①当3的x次方=2时,求(1/9)²-1的值
②已知x-y=1,求x²-y²+3x-5y
1、计算:①(2+1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)②(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^152、①当3的x次方=2时,求(1/9)²-1的值②已知x-y=1,求x²-y²+3x-5y
1.(2+1)(2^2+1)……(2^2048+1)
=(2-1)(2+1)(2^2+1)……(2^2048+1)/(2-1)
=(2^2-1)(2^2+1)(2^4+1)……(2^2048+1)
=……
=2^4096-1
2.(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^15
=(1-1/2)(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)/(1-1/2)+1/2^15
=……
=(1-1/2^16)/(1/2)+1/2^15
=2-1/2^15+1/2^15
=2
3^x=2
(x/9)²-1=x^2/9^2 -1=4/81 -1=-77/81
应该是(x/9)^2-1吧?
x-y=1,
x^2-y^2+3x-5y=(x+y)(x-y)+3x-5y=x+y+3x-5y=4x-4y=4(x-y)=4
①=(2-1) *(2+1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)
=(2^2-1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)
=...=2^4096-1
②=(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^15
②/2=(1- 1/2)(1+1/2)(1+1/2^2)(1...
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①=(2-1) *(2+1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)
=(2^2-1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)
=...=2^4096-1
②=(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^15
②/2=(1- 1/2)(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^15
②/2=(1-1/2^2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^15
2=1-1/2^16+1/2^15=1+1/2^16
②=2+1/2^8
3^x=2
(x/9)²-1=x^2/9^2 -1=4/81 -1=-77/81
x²-y²+3x-5y=(x-y)(x+y)+3(x-y)-2y=x+y+3-2y=x-y+3=1+3=4
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①(2+1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)
=(2-1)(2+1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)
=(2^2-1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)
=(2^4-1)(2^4+1)(2^8+1)…(2^2048+1)
=....
...
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①(2+1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)
=(2-1)(2+1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)
=(2^2-1)(2²+1)(2^4+1)(2^8+1)…(2^2048+1)
=(2^4-1)(2^4+1)(2^8+1)…(2^2048+1)
=....
=2^4096-1
②(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^15
=2*(1-1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)+1/2^15
=2*(1-1/2^4)(1+1/2^4)(1+1/2^8)+1/2^15
=2*(1-1/2^8)(1+1/2^8)+1/2^15
=2(1-1/2^16)+1/2^15
=2-1/2^15+1/2^15
=2
2. ①当3的x次方=2时,求(1/9)²-1
题目好像有问题
②x-y=1,
x²-y²+3x-5y=(x-y)(x+y)+3x-5y
=(x+y)+3x-5y
=4(x-y)
=4
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