OCR MEI C4 — Question 3

Exam BoardOCR MEI
ModuleC4 (Core Mathematics 4)
TopicDifferential equations

3 In a chemical process, the mass \(\boldsymbol { M }\) grams of a chemical at time \(\boldsymbol { t }\) minutes is modelled by the differential equation $$\underset { d t } { d \underline { \underline { M } } } - \underset { \mathrm { z } \left( \left. \right| ^ { \prime } + \mathrm { z } ^ { 2 } \right) ^ { \prime } } { M _ { - } }$$
  1. Find \({ } _ { \mathrm { f } } \overline { 1 } ; \overline { 12 } d t\)
    (li) Find constants \(\boldsymbol { A } , \boldsymbol { B }\) and \(\boldsymbol { C }\) such lhat $$\begin{array} { c c } 1 & B t + C
    \hdashline t \left( I + t ^ { 2 } \right) & I \end{array} . + \begin{array} { c c } I & I + 1 ^ { 2 } . \end{array}$$
  2. Use integration, together with your results in parts (i) and (ii), to show that $$M = \frac { K t } { J \sqrt { + , 2 } } ,$$ where \(\boldsymbol { K }\) is a constant.
  3. When \(\boldsymbol { t } = \mathrm { I } , \boldsymbol { M } = 25\). Calculate \(\boldsymbol { K }\) What is the mass of the chemical in the long term?