# quinn

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### can someone prove sin2x=2*sinx * cosx for me?Thank you

quinn  Oct 10, 2014
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### In a trail,supposea lawyer wants 2 men and 5 womento make up a special panel. so the formlar is nCr=n!/[r!*(n-r)]!,right?So,5C2=5!/[2!(5-2)]

quinn  Oct 9, 2014
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### in the figure ,cntral ganle BAC is 30 degrees. If circle A has a diamter of 6 units , what is the area of the shaded segment

quinn  Oct 8, 2014
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### if a,b,care the 3 sides of the triangle ABC,and a^2+b^2+c^2=ab+bc+ac.what is the shape of the triangle?

quinn  Sep 30, 2014
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quinn  Sep 28, 2014
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### does the equation 4^x=x have a soloution?

quinn  Sep 26, 2014
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### In the triangle ABC, a,b,c are the 3 sides of the triangle.if a(1-x^2)+2bx+c(1+x^2)=2 is a qudratic equation. The equation have two same sol

quinn  Sep 26, 2014
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### if x^2-2011x+1=0 is true,then waht is the value of x-2010x+2011/(x^2+1)?

quinn  Sep 25, 2014