請各位高手幫幫忙,一道數學題。解的出最好,解不出也有回報!!
①14(a^2+b^2+c^2)=(a+2b+3c),求證a∶b∶c=1∶2∶3。最好有過程,也可以寫思路。隨你。應該是這樣的
14(a^2+b^2+c^2)=(a+2b+3c)^2
14a^2+14b^2+14c^2)=a^2+4b^2+9c^2+4ab+12bc+6ac
13a^2+10b^2+5c^2-4ab-12bc-6ac=0
(2a-b)^2+(3b-2c)^2+(3a-c)^2=0
2a=b,a/b=1/2
3b=2c,b/c=2/3
3a=c,a/c=1/3
a:b:c=1:2:3
14(a^2+b^2+c^2)=(a+2b+3c)^2
14a^2+14b^2+14c^2)=a^2+4b^2+9c^2+4ab+12bc+6ac
13a^2+10b^2+5c^2-4ab-12bc-6ac=0
(2a-b)^2+(3b-2c)^2+(3a-c)^2=0
2a=b,a/b=1/2
3b=2c,b/c=2/3
3a=c,a/c=1/3
故a:b:c=1:2:3
各位高手,做這道題!幫幫忙!!!!謝謝了!!!!!
Listen and wite the sentences.rn1.A:What does Katie always do at 6:05?rn B:She always __________.(wash face)rn2.A:What does Katie usually do after she washes her face?rn B:She usually___________.(make bed )rn3.A:What does the family usually do at 6:30 am?rn B:The family usually_______________________.(has breakefast)rn4.A:How do Katie and Sally go to school every day?rn B:They always__________________.(by bus)washes face
makes bed
has breakefast
by bus
face
make
breajefast
bus
呵呵。其實括號里面的就是答案了。
wash face,make bed,has breakfast,by bus.
washing face
makes bed
has breakfast
by bus
face
bed
has breakefast
by bus
請各位高手幫我看一下這道題,謝謝
number介于300與500之間,
即300<number≤500,
不能寫成300<number>=500,這是錯誤的,正確的寫法是:
number>300&&number<=500
你把你的程序中的三行類似表述都改過來,應該就好了。
if(300<number>=500),這里有問題吧
改成if(300<number<=500),同理改下下面兩個if里的判定條件
這樣看沒什么問題!能運行嗎?
各位數學高手,幫我解下這幾道題,謝謝~
這幾題只要最后答案:(1) -(a^5)^4÷(a^2)^3 (2) 分解因式:x^2-8x+16=___。 (3)已知1-a^n=(1-a)(1+a)(1+a^2)(1+a^4),那么n的值是___。rn這幾題要答案和全過程:(4)(x-1/4)(x+1/4)(x^2+1/16)rn(5)解方程或不等式:2(x-3)(x+5)=x^2+(x+2)×(x-2)+x+7rn要最后答案:(x+2)(x-3)=rn (x-2)(x+3)=rn大家幫我算下可以嗎?謝謝(1) -(a^5)^4÷(a^2)^3=-a^14
(2) 分解因式:x^2-8x+16=_ (x-4)^2
(3)n=8
(4)(x-1/4)(x+1/4)(x^2+1/16)
=(x^2-1/16)(x^2+1/16)
=x^4-1/256
(5 ) 2(x-3)(x+5)=x^2+(x+2)×(x-2)+x+7
2x^2+4x-30=x^2+x^2-4+x+7
3x=33
x=11
:(x+2)(x-3)=x^2-6
(x-2)(x+3)=x^2-6
(1) -a^14
(2) (x-4)^2
(3) 8
(4) 用平方差公式
(x-1/4)(x+1/4)(x^2+1/16)
=(x^2-1/16)(x^2+1/16)
=x^4-1/256
(5) 2(x^2+2x-15)=x^2+(x^2-4)+x+7
2x^2+4x-30-x^2-x^2+4-x-7=0
4x-30+4-x-7=0
3x=33
x=11
(6) (x+2)(x-3)=x^2-x-6
(x-2)(x+3)=x^2+x-6
(1) -(a^5)^4÷(a^2)^3=-a^14
(2) 分解因式:x^2-8x+16=_ (x-4)^2
(3)n=8
(4)(x-1/4)(x+1/4)(x^2+1/16)
=(x^2-1/16)(x^2+1/16)
=x^4-1/256
(5 ) 2(x-3)(x+5)=x^2+(x+2)×(x-2)+x+7
2x^2+4x-30=x^2+x^2-4+x+7
3x=33
x=11
:(x+2)(x-3)=x^2-6
(x-2)(x+3)=x^2-6這些都不會,你做的題目符不符合你的年級?
果斷都太簡單了~身為大學生做這些題目會被鄙視的,所以對不住
我自己都 不會 呵呵
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