Unit5 - Square and cube roots

Sumary of Knowledge



The goals for this unit are to understand and know how to make square and cube roots , and know how to estimate a cube and square root. It is important for electrical ingeneers to calculate power factors and electrical load distribution when dealing with 3 face power conections.







Key vocabulary

Irrational number: A number that cannot be expressed as a ratio between two integers and is not an imaginary number. If written in decimal notation, an irrational number would have an infinite number of digits to the right of the decimal point, with out repetition.








Square root: A number or quantity that multiplied by itself gives a given number or quantity.








Cube root:The number that is multiplied by itself three times that gives a given number or quantity.



Task Analysis


Square Root


For finding the square root you need to find a number that multiplied by itself gives you the number that is involved in the equation.

Cube Root


For finding the cubic root of a number you need to find a number that multiplied by itself 3 timesFgives you the number that is involved in the equation





Aproximate Square Root




If you can´t find a number that muliplied by itself gives you the number that is involved in the equation ,you need to find the numbers that it is in between and then you put the numbers that are at the sides as an answer.



Examples

Square Root

√81= ? √81=9
7*7=49
8*8=64
9*9=81

Cube root

∛125= ? ∛125= 5
4*4= 16*4= 64
5*5= 25*5= 125

Aproximate Square Root

√20 is between the square root of 16 and the square root of 25
√16= 4 and √25= 5
so √20 is between 4 and 5. That means that it is irrational.





Additional Help






Games:

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