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> ***i)*** Explain why: $T'(t)+kT(t)=3kt$
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So, here is what I did:

Let the room temperature be $A(t)$ and $dA/dt=3$

If we use the formula for Newton's law of cooling/heating: $$T'(t)=k(A(t)-T(t))$$

$$T'(t)=3kt-kT(t)$$

$$T'(t)+kT(t)=3kt$$
I let $A(t)= 3t$ and $A'(t)=3$

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> ***ii)*** If $T(0)=0$, find $T(t)$ expressed in terms of $k$
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