Quandaries and Queries



Hi, I have a career link question from gr.12 advanced functions and intro. calculus. The equations is:

R(t) = 5(t4 - 4t3 + 19/4 t2 - 3/2 t)

The question is to apply the factor theorem and quadratic formula to determine the times it crosses the t axis. The only method i know of for using the factor theorem is when the last number does not have a variable beside it so i'm not sure how you would even use the factor theorem for this? We haven't dealt with any that have 0 as the last number with no variable so i'm a little confused! please help!

Thank you



Hi LisaMarie,

What you need to see is that t is a common factor in the expression for R(t). You can take it out as a common factor to get

R(t) = 5t(t3 - 4 t219/4 t -  3/2)

To use the factor theorem you want all the coefficients to be integers so put the expression inside the parentheses over a common denominator of 4 to get

R(t) = 5/4 t(4 t3 - 16 t2 + 19 t -  6)

Now apply the factor theorem.



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