Thread: Irregular powers without a calculator

1. Irregular powers without a calculator

How would I evaluate 9^(3/2) without a calculator?

2. Originally Posted by Naur
How would I evaluate 9^(3/2) without a calculator?
see post #3 here, then you tell us

3. WELL then I'd go 9^3 = 729, and then I'd root 729: 729^.5 = 27.
And that works fantastically, thank you. But at the same time, it seems like it's cutting out even more work for myself. Though it works, I've got a timed exam coming up that I'm preparing vigorously for, and doing 9 cubed isn't going to save time...
Do you know a quicker way? I could always verify with that method once I've finished the questions....

Thanks a heap though

4. Originally Posted by Naur
WELL then I'd go 9^3 = 729, and then I'd root 729: 729^.5 = 27.
And that works fantastically, thank you. But at the same time, it seems like it's cutting out even more work for myself. Though it works, I've got a timed exam coming up that I'm preparing vigorously for, and doing 9 cubed isn't going to save time...
Do you know a quicker way? I could always verify with that method once I've finished the questions....

Thanks a heap though
wouldn't it be easier to square root the 9 first and then cube the result?

5. Why yes it would. Thanks very much.
That'll do nicely.