The root of a number is that number which, when multiplied by itself so many times, equals the given number; the 'square' root of 4 is 2, ie 2 X 2 = 4, and this is written thus
Similarly the 'cube' root of 8 is 2, ie 2 x 2 x 2 = 8, and
etc. Note the little 2 in the sign for square root is normally omitted so that
√ signifies the square root.
The following should be memorised as they can prove to be very useful
For example
It is always worth checking to see if the number left after dividing by 2, 3 or 5 is a perfect square.
The square root of a number expressed in the index notation is found by dividing the index by 2, thus √106 = 103 and √1012 = 106 and so on. Similarly √10-6 = 10-3 etc. Should the index be an odd number, it must be made into an even number as follows.
The constant term π occurs in many calculations has great significance in mathematics and is the ratio of the circumference to the diameter of a circle. π can be taken to be 3.14 or 22/7. The error in taking π2 as 10 is less than 1.5% and is acceptable here. 1/π can be taken as 0.32 and 1/2π can be taken as 0.16 (The error is calling this 1/6 is too high and should be avoided). The 1/2π = 0.16 is particularly useful to remember as the constant 1/2π is common in electronics.
