Exercise 70 Page 420

To simplify the given expression, we can first rewrite the radical as a quotient of two radicals. sqrt(3x^3/2y)=sqrt(3x^3)/sqrt(2y) Now, we can rationalize the denominator of the quotient. Let's multiply the numerator and denominator by a factor that will make the denominator a perfect fifth power inside the fifth root. We will do this using the fact that we can multiply the radicands of radicals if they have the same index. If sqrt(a) and sqrt(b) are real numbers, then sqrt(a)* sqrt(b)= sqrt(ab). Let's start by finding the exponents necessary to create perfect fifth powers in the denominator. Our goal is to have five of each factor.

sqrt(3x^3)/sqrt(2y)

WritePow

Write as a power

sqrt(3x^3)/sqrt(2^1y^1)

ExpandFrac

a/b=a * sqrt(2^4y^4)/b * sqrt(2^4y^4)

sqrt(3x^3)*sqrt(2^4y^4)/sqrt(2^1y^1)*sqrt(2^4y^4)

MultRoot

sqrt(a)*sqrt(b)=sqrt(a* b)

sqrt(3x^3*2^4y^4)/sqrt(2^1y^1*2^4y^4)

MultPow

a^m*a^n=a^(m+n)

sqrt(3x^3*2^4y^4)/sqrt(2^5y^5)

Now that we have found the factors that will make the radicand of the denominator perfect fifth powers only, we can begin to simplify the quotient. While simplifying, we should remember that all variables are positive, so sqrt(a^n) = a.

sqrt(3x^3*2^4y^4)/sqrt(2^5y^5)

CalcPow

Calculate power

sqrt(3x^3*16y^4)/sqrt(2^5y^5)

SplitIntoFactors

Split into factors

sqrt(3* x* x* x* 2* 2* 2* 2* y* y* y* y)/sqrt(2^5y^5)

CommutativePropMult

Commutative Property of Multiplication

sqrt(2* 2* 2* 2* 3* x* x* x* y* y* y* y)/sqrt(2^5y^5)

RootPowToNumber

sqrt(a^3)=a

sqrt(2* 2* 2* 2* 3* x* x* x* y* y* y* y)/2y

Multiply

Multiply

sqrt(48x^3y^4)/2y