right arrow
Examples: Monday, today, last week, Mar 26, 3/26/04

Math question

cookie97cookie97 0 replies1 discussions Forum Champion
Hey guys,
I was doing a math problem, but it seems to have two answers, one positive and one negative, and I'm confused which one it is.
The question is:
what is sqrt(-4) * sqrt (-25)?

One way to do is 2i*5i= -10
Another way is sqrt(-4*-25)= sqrt(100)= 10.
Which one is the correct answer?
1 replies
Post edited by cookie97 on
· Reply · Share

Replies to: Math question

  • mash101mash101 18 replies1 discussions
    The answer is -10. When you are working with multiple imaginary square roots, you must first solve them out separately. So in this case, you would first solve for 2i and then 5i, THEN multiply them to get 10i^2 = -10. I learned this in class earlier this year.
    edited May 2013
    · Reply · Share
Sign In or Register to comment.

Recent Activity