# Simplified Radical Form with square and cubed roots

## Main Question or Discussion Point

I just got a new Ti-nspire Cx CAS calculator and I am having trouble with being able to express a Radical in simplified form when there are exponents and variables of x and y. My problem is that this calculator will not show the simplified form correctly. I have taken others advice in setting the calculator to exact mode but I suspect that the other settings in this same area are wrong.

I currently have the settings at: Display Digits-Float 6, Angle-Degree, Exponential Format-Normal, Real or Complex-Real, Calculation Mode-Exact, Vector Format-Rectangular, Base-Decimal, Unit system-Eng/US.

Does anyone know what all of the settings should be? Any advice would be helpful at this point.

Example issue is that when I enter:
√68x2y I get 8√x5y and the correct answer is 8x2√xy and incase my typed questions are confusing, the x2, x5, x2 - the 2,5,2 are exponents.

Thanks

Mark44
Mentor
I just got a new Ti-nspire Cx CAS calculator and I am having trouble with being able to express a Radical in simplified form when there are exponents and variables of x and y. My problem is that this calculator will not show the simplified form correctly. I have taken others advice in setting the calculator to exact mode but I suspect that the other settings in this same area are wrong.

I currently have the settings at: Display Digits-Float 6, Angle-Degree, Exponential Format-Normal, Real or Complex-Real, Calculation Mode-Exact, Vector Format-Rectangular, Base-Decimal, Unit system-Eng/US.

Does anyone know what all of the settings should be? Any advice would be helpful at this point.

Example issue is that when I enter:
√68x2y I get 8√x5y and the correct answer is 8x2√xy and incase my typed questions are confusing, the x2, x5, x2 - the 2,5,2 are exponents.
That's not all that's confusing. One way to indicate exponents here at Physics Forums is to use the caret character ^. So x^2 represents the square of x, and so on.

With √68x2y, it's not clear what is under the radical.

This looks to me like √6 ##\cdot## 8x2 ##\cdot## y, but it could also be √(68) ##\cdot## x2 ##\cdot## y, or any of several other possibilities.

Since your answers come out with 8 and some other factors, the number must be 64, not 68 as you show.

If this is the expression you're working with -- √(64x^2 y)-- , then you should end up with 8x √y.

The problem that I'm working with is actually √(64x^5 y) and the correct answer is 8x^2√xy
I realize that 8(8) is 64 and that I have to borrow one from five and show the square root of four, which is two, leaving a remainder of one, thus the reason for 8x^2√xy but my calculator will not show the correct answer.

Sorry about the confusion. I am new at this calculator. Can you tell me why the Ti-nspire Cx CAS will not simplify it showing the correct answer?

Mark44
Mentor
The problem that I'm working with is actually √(64x^5 y) and the correct answer is 8x^2√xy
This really should be 8x^2√(xy), with the parentheses used to show that the square root is of the product xy, not just x.
I realize that 8(8) is 64 and that I have to borrow one from five and show the square root of four, which is two, leaving a remainder of one, thus the reason for 8x^2√xy but my calculator will not show the correct answer.
I'm guessing that you might not be using parentheses when you enter the expression. I don't have one of these calculators, so I can't say for sure.

If you enter √(64x^5y) it should produce 8x^2√(xy).