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Select the pair of consecutive integers between which a real zero of f(x) = x3 + 5x2 –x – 6 exists.

A)-6, -5

B)-2, -1

C)2, 3

D)-4, -3

 

Write the polar form of the complex number 3-2i, using θ such that 0 ≤ θ ≤ 360º. Round numerical values to the nearest hundredth.

 

A)3.61(cos 326.31º - i sin 326.31º)

B)326.31(cos 0.61º + i sin 3.61º)

C) 326.31(cos 326.31º - i sin 326.31º)

D) 3.61(cos 326.31º + i sin 326.31º)

 

 

The function f(x) = 8x4 – 72x3 +144x2 has ____ possible zeros.

A) none 

B) four

C) one

D) three

 

 

 

 Nov 4, 2014

Best Answer 

 #1
avatar+27558 
+5

First question.  These graphs might help:

Zeros?

 

 

In general, insert the two values into the function.  If the results are of opposite sign there is a zero between them.

 

Second question

See Chris's answer here: http://i61.tinypic.com/17coq9.png 

 

Third question.

Because this is a 4th order polynomial there are 4 roots.  However, in this case two of them are the same (there are two roots with x = 0).  The other roots are at x = 3 and x = 6.

.

 Nov 5, 2014
 #1
avatar+27558 
+5
Best Answer

First question.  These graphs might help:

Zeros?

 

 

In general, insert the two values into the function.  If the results are of opposite sign there is a zero between them.

 

Second question

See Chris's answer here: http://i61.tinypic.com/17coq9.png 

 

Third question.

Because this is a 4th order polynomial there are 4 roots.  However, in this case two of them are the same (there are two roots with x = 0).  The other roots are at x = 3 and x = 6.

.

Alan Nov 5, 2014

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