Firstly, let’s review what a radical is. A radical is a mathematical expression that contains a root. The most common radical is the square root, which is represented by the symbol √. The radical √x means the square root of x. For instance, √9 equals 3 because 3 x 3 = 9.
When you are multiplying radicals, there are a few different methods you can use depending on the types of radicals you are working with. Here are three methods to consider:
1. Multiplying two identical radicals:
If you’re multiplying two identical radicals, such as √x and √x, you can simply multiply the radicands (that is, the numbers under the radical sign) together. The product of √x and √x is √x². Since the square of a square root is just the number inside the radical sign, we simplify this expression to x. Therefore √x √x = x. For example, √5 × √5 = √25 = 5.
2. Multiplying radicals with the same index:
If you are multiplying two radicals with the same index, such as √x and √y, you can use the product rule of radicals. The product rule of radicals states that the product of two radicals with the same index is the same as a single radical with the same index that has the product of the radicands as its radicand. Mathematically, it can be expressed as √x × √y = √xy. For example, √6 × √9 = √54.
3. Multiplying radicals with different indexes:
If you are multiplying two radicals with different indexes, such as √x and ³√y, you have to rationalize the denominators first. Rationalizing the denominators means to multiply both numerator and denominator of each radical by the necessary expression to eliminate the radical in the denominator. For instance, to simplify √x/³√y, you can multiply both numerator and denominator by ³√y², which yields √x׳√y² /³√y׳√y² = √xy²/3√y³.
Overall, multiplying radicals is not too difficult once you understand the different methods to use. It can require some practice to get comfortable with working with radicals. The key is to remember the rules and properties, such as the product rule of radicals, and to simplify your answer by looking for opportunities to cancel out terms. With that in mind, you’ll be able to confidently tackle problems that involve multiplying radicals.