Index Notation.

42 =2×3×7 here 2,3,7 are factors of the product 42.

45=3×3×5 here 3,3,5 are factors of the product 45.

Similarly in ab ,a and b are the factors of ab.

In 7xy, 7,x,y are factors of 7xy.

 

Thus ,when numbers or letters standing for numbers are multiplied together to form a product ,each of them is called a factor of that product.

 

When the same factor is repeated in a product we use a different mode of writing the product.

 

 

 

 

and a×a×a=

 

 

 

is called the fourth power of a and we say it as a to the fourth power.

 

 

2 is called as the index or exponent of the power.

 

Note: If index is unity it is omitted. Thus a stands for

 

 

They all have same meaning

 

a, 1a, a .