当a=-1时,求16 2a-8a-[a-9-3-6a]的值
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原式=(a+1)/(a-1)-[a/(1/a)]/(a-2a+1)=(a+1)/(a-1)-a/(a-1)=[(a+1)(a-1)-a]/(a-1)=(a-1-a)/(a-1)=-1/(a-1)a=-
a-(a+b)+(a+2b)-(a+3b)+……-(a+101b)=a+(a+2b-a-b)+(a+4b-a-3b)+...+(a+100b-a-99b)-a-101b=a+b+b+...+b-a-1
a=1/(√3+2)=(2-√3)/(√3+2)(2-√3)=(2-√3)/(4-3)=2-√3a-1=1-√3
a-(a+b)+(a+2b)-(a+3b)+……-(a+101b)=a+(a+2b-a-b)+(a+4b-a-3b)+...+(a+100b-a-99b)-a-101b=a+b+b+...+b-a-1
(5a³-2a²-6a+6)-(3a³-3a²-8a+3)+(-2a³-a²-2a+2)=5a³-2a²-6a+6-3a
10-(1-a)-(1-a-a²)+(1+a-a²-a³)=10-(1-1/2)-(1-1/2-1/4)+(1+1/2-1/4-1/8)=10-1/2-1/4+9/8=8
(5a+2a²-3-4a²)-(-a+3a³-a²)=5a-2a²-3+a-3a³+a²=-3a³-a²+6a
a=√3>1a-1>0|a-1|=a-1原式=[(a-1)²/(a-1)]-√(a-1)²/a(a-1)=(a-1)-|a-1|/a(a-1)=a-1-(a-1)/a(a-1)=a
15a^2-{-4a^2+[5a-8a^2-(2a^2-a)+9a^2]-3a}=15a^2-{-4a^2+[5a-8a^2-2a^2+a+9a^2]-3a}=15a^2-{-4a^2+[6a-a^2
原式=(a-1)²/(a+1)(a-1)+2a(a-2)/(a+1)(a-2)=(a-1)/(a+1)+2a/(a+1)=(3a-1)/(a+1)=(√3-1)/(√3/3+1)=3(√3-
当a=-1时A=a²-2a+1=1+2+1=4B=-3a²-4a+2=-3+4+2=3∴3A-B=3*4-3=9
因为a^m=3,a^n=1/2所以a^3m+a^2n=3³+(1/2)²=109/4
16-2-{-8-[-1-9-(3+6)]}=3再问:还要先化简,在求值再答:16+2a-{8a-[a-9-(3-6a)]}=16+2a-[8a-(a-9-3+6a)]=16+2a-(8a-7a+12
原式=(7a²-5a²-a²)+(-4a+a+4a)+(1+2)=a²+a+3=9+3+3=15
当a=1时,a-2a+3a-4a+5a…+99a-100a=1-2+3-4+……+99-100=(-1)×50=-50
已知:f(x)=sin(x+a)+√3cos(x-a);(1)当f(x)为偶函数时求a;(2)当f(x)为奇函数时求a.(1)当f(x)为偶函数时,f(-x)-f(x)=0,则[sin(-x+a)+√
3A-B=3(a^2-2a+1)-(-3a-4a+2)=6a^2-2a+1a=-1,3A-B=9