Question

What are the zeros of the function f(x)=x^4-4x^2-5

Answer 1

`x =√(5) ,-√(5) ,-i,i`

Step-by-step solution:

`0=x^4-4x^2-5`
`u = x^2`

`0 = u^2-4u-5`

`0 = (u -5)(u+1)`

`u = 5`
`u=-1`

`x^2 =5`
`x^2 = -1`

`x= +-√(5)`
`x = +-i`