\(VP=\left(a+b\right)^2-4ab\)
\(=a^2+2ab+b^2-4ab\)
\(=a^2-2ab+b^2\)
\(=\left(a-b\right)^2=VT\)
Vậy \(\left(a-b\right)^2=\left(a+b\right)^2-4ab\)
chứng minh rằng
\(\left(a+b\right)^2=\left(a-b\right)^2+4ab\)
\(\left(a-b\right)^2=\left(a+b\right)^2-4ab\)
Bài 8.CM các hằng dẳng tức sau
1) \(\left(a+b\right)^2-\left(a-b\right)^2=4ab\)
2) \(\left(a+b\right)^2+\left(a-b\right)^2=2\left(a^2+b^2\right)\)
3) \(\left(a+b\right)^2-4ab=\left(a-b\right)^2\)
4)\(\left(a-b\right)^2+4ab=\left(a+b\right)^2\)
Chứng minh rằng
a) ( a + b ) = \(\left(a-b\right)^2\)+ 4ab
b) \(\left(a-b\right)^2\)= \(\left(a+b\right)^2\)- 4ab
Chứng minh :
\(\left(a+b\right)^2-\left(a-b\right)^2=4ab\)
\(a\left(b-c\right)^2+b\left(a-c\right)^2+c\left(a-b\right)^2-a^3-b^3-c^3+4ab\) nếu ko thấy thì là +4ab
\(a\left(b^3-c3\right)+b\left(c^3-a^3\right)+c\left(a^3-b^3\right)\)
Chứng minh rằng:
a)\(a^3+b^3=\left(a+b\right)^3-3ab\left(a+b\right)\)
b)\(\left(a-b\right)^3+3ab\left(a-b\right)=a^3-b^3\)
c)\(\left(a+b\right)^2-\left(a-b\right)^2=4ab\)
Chứng Minh rằng
\(\left(a+b\right)^2\)=\(\left(a-b\right)^2\)+4ab
Chứng minh các đẳng thức:
a)\(\left(x-y\right)\left(x^3+x^2y+xy^2+y^3\right)=x^4-y^4\)
b)\(\left(a+b\right)^2-\left(a-b\right)^2=4ab\)
1/ CMR : \(\left(a+b\right)^2=\left(a-b\right)^2+4ab\)
\(\left(a-b\right)^2=\left(a+b\right)^2-4ab\)
2/ Tính :
\(\left(a+b+c\right)^2\)
