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The mass, m grams, of a substance is increasing exponentially so that the mass at time t hours is m=250e^(0.021t). Find the time taken for the mass to double in value.

All exponential equations can be reduced to the form m=m 0 e kt , where m 0 is the initial mass. This means for our equation the initial mass is 250g. If the mass has doubled in size, then m now equals 2*250...
TJ
Answered by Tom J. • Maths tutor
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How can I determine the stationary points of a curve and their nature?

For example, y = 3x 3 + 9x 2 + 2. Determine the stationary points and their nature. Let's remind ourselves what a stationary point is, and what is meant by the nature of the points. A stationary point is a p...
TD
Answered by Tutor87017 D. • Maths tutor
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Find all the solutions of 2 cos 2x = 1 – 2 sinx in the interval 0 ≤ x ≤ 360°.

We know that having cos and sin functions in a question is going to cause us problems - we need a single function of x. So, step 1, we need to rewrite sin or cos in terms of the other. How do we choose which...
NH
Answered by Nicola H. • Maths tutor
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How do you expand (2x-1)(3x+4) using the FOIL method?

First, we must understand what the FOIL method is. FOIL is an ancronym that we use to help us remember the steps when expanding brackets. F - first O - outer I - inner L- last Step 1: Multiply the FIRST term...
JL
Answered by James L. • Maths tutor
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Factorise and solve the quadratic equation x^2 + 6x + 8 = 0

Theory Problems like this need to be broken down into steps: i) Factorise, ii) solve and iii) check. The aim of this question is to find values of x which satisfy the quadratic equation, i.e. when we substit...
TD
Answered by Tutor87306 D. • Maths tutor
10611 Views