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# Fp1 roots question

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1. Can any one show me how to find the two roots in (4x^2 +9)?
2. (Original post by SakuraE)
Can any one show me how to find the two roots in (4x^2 +9)?
Are you familiar with using the discriminant to determine the nature of the roots of a function? b^2 - 4ac?
3. (Original post by SakuraE)
Can any one show me how to find the two roots in (4x^2 +9)?
4x^2+9=0

4x^2=-9
x^2=-9/4
x=sqrt of -9/4

x=+3/2i and -3/2i
4. (Original post by maruchan)
4x^2+9=0

4x^2=-9
x^2=-9/4
x=sqrt of -9/4

x=+3/2i and -3/2i
Assumed they have covered complex roots!
5. (Original post by SakuraE)
Can any one show me how to find the two roots in (4x^2 +9)?
6. (Original post by offhegoes)
Assumed they have covered complex roots!
yes!
7. (Original post by offhegoes)
Assumed they have covered complex roots!
Which is in the syllabus for FP1, yes.
8. Thank you I get it now I put it through the quadratic formula and it came out as +and - 3/4i
9. (Original post by SakuraE)
Thank you I get it now I put it through the quadratic formula and it came out as +and - 3/4i
That doesn't look quite right.
10. (Original post by Zacken)
That doesn't look quite right.
after looking through all my workings it seems that as there was two 4s under the radical sign I accidentally missed one when I multiplied it out

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