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1.5.6 Polynomials and rational expressions

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Question 73

The rate of mass accumulation in a sediment trap, MMM (in mg/year), is modeled by the function:

M(t)=4t3+5t2−12t+15t2+3,t≥0 M(t) = \frac{4t^3 + 5t^2 - 12t + 15}{t^2 + 3}, \quad t \ge 0 M(t)=t2+34t3+5t2−12t+15​,t≥0

where t t\,t is the time in years since the study began.

Given that

M(t)≡At+B+Ct+Dt2+3 M(t) \equiv At + B + \frac{Ct + D}{t^2 + 3} M(t)≡At+B+t2+3Ct+D​
a.

(i) Find the values of the constants AAA, B B\,B and CCC.

(ii) Show that D=0D = 0D=0.

[4]
b.

Hence, using algebraic integration, find the total mass accumulated between t=1t = 1t=1 and t=3t = 3t=3, giving your answer in the form p+qln⁡kp + q \ln kp+qlnk, where ppp, q q\,q and k k\,k are integers and k k\,k is prime.

[4]

1.5.6 Polynomials and rational expressions Questions

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