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C4 June 2014 Q4: Water is flowing into a vase. When the depth of water is h cm, the volume of water V cm^3 is given by V=4πh(h+4). Water flows into the vase at a constant rate of 80π cm^3/s. Find the rate of change of the depth of water in cm/s, when h=6.

This question wants us to find: dh/dt. We are given: dV/dt=80π and V=4πh(h+4). The equation to use here is: dh/dt = dh/dV x dV/dt. We kn...

Answered by Suban K. • Maths tutor

7982 Views

How do you differentiate y=cox(x)/sin(x)?

Since we have to differentiate a fraction, we must use the quotient rule.

The quotient rule: If y = u/v, dy/dx = (vdu/dx - udv/dx)/v²

So we must work out each of the ter...

Answered by Raj C. • Maths tutor

5103 Views

I don't understand when to use the subjunctive and how to conjugate it?

In English, the subjunctive is used to express wishes or hypothetical situations, e.g. I wish you were nicer to me ('were' is in the subjunctive). In French, it's fairly similar. The subjunctive is associ...

Answered by Iona S. • French tutor

1914 Views

How do I solve simultaneous equations?

2x + y = 7

3x - y = 8

You cannot find x and y using only one equations, but using both you can! So first you have use algebra to make both equations = y. Try this for the first equation by r...

Answered by Stephanie O. • Maths tutor

2573 Views