Question

(x + y)2 = x2 + 2xy + y2
this identity example
only one

Answer 1

Step-by-step explanation:

a²+b²=(a+b)²

(a+b)²=a²+2ab+b²

hance proved

Answer 2

This identity is used in complex numbers. Complex numbers are the numbers with the imaginary unit, i(square root of -1). The examples are $\sqrt{-1}$, 1+i.

Since complex numbers take on algebraic expressions, we can square, multiply, divide, add, subtract.

$(1+i)^2=1+i+i+i^2=1+2i-1=2i$

If you are curious about the square roots of i, such numbers give you i after squaring.

$\sqrt{i} =\frac{\sqrt{2i} }{\sqrt{2} }$

1+i gave 2i after squaring. So, the square root of 2i is 1+i.

$\sqrt{i} =\frac{1+i}{\sqrt{2} }$

Don't forget that there exists no sign in complex numbers! -1 multiplied to the number is also the square root.

$\dfrac{1+i}{\sqrt{2} }$ or $-\dfrac{1+i}{\sqrt{2} }$ are square roots of i.