We use roots to express the inverse operation of exponentiation.
For example, if we have x², the square root helps us find the original number x when we know x². In other words, the square root of a number x is the value y that, when multiplied x by itself, gives y.
Basic rules of roots:
- Square Root: The square root of a number x is written as √x and means a number that when squared equals x. Ex. 32 = 3*3 = 9, 652 = 65*65 = 4225 ( Using the rule for numbers ending in 5: multiply the first part by its successor and append 25.)
- n-th Root: The n-th root of a number x is written as ⁿ√x and means a number that, when raised to the power n, equals x.
- Product Rule: √(a × b) = √a × √b
- Quotient Rule: √(a / b) = √a / √b, where b ≠ 0
- Root of a power: ⁿ√(xm) = xn/m
- Nested roots: ⁿ√(ᵐ√x) = ᵐⁿ√x = x(1/(m·n))
Examples:
- √81 = 9 because 9 × 9 = 81
- √144 = 12 because 12 × 12 = 144
- √144*25 =√144 * √25 = 12 * 5 =60
- √225/25 = √225 / √25 = 25 / 5 = 5
- √(22 ) = 22/2 = 21 = 2
- 2√(5√x) = 2*5√x = x1/10
KEEP IN MIND
The square root symbol √, when written without an index, implicitly represents the second root.
For higher roots, the index n must be specified as √[n]{x} = x(1/n) to distinguish them.
To solve a nested roots problem in mathematics, follow these steps:
To solve the problem √√√1000
- Start with the innermost square root: √1000
Calculate √1000 ≈ 31.6228 - Next, take the square root of the result: √31.6228
Calculate √31.6228 ≈ 5.6234 - Finally, take the square root once more: √5.6234
Calculate √5.6234 ≈ 2.3714
To solve √√√1000 by calculating roots together, first recognize that:
√√√1000 = √2*2*2 (1000)= √8 (1000) = 10001/8
Now calculate:
1000(1/8) = (103)(1/8) = 10(3/8) ≈ 100.375 ≈ 2.3714
So, √√√1000 ≈ 2.3714 in both ways.
So, when dealing with nested roots, you need to multiply their indexes to simplify the expression correctly.
This works because taking the (m)-th root and then the (n)-th root is the same as taking the ((n \times m))-th root once. So, multiplying the indexes combines the nested roots into one root with the product of the original indexes.

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