Top answers

How is the cardiac cycle regulated by the heart itself?

The heartbeat is started at a specialised area of the right atrium, known as the sinoatrial node (SAN) ; the SAN sends out the waves of depolarisation, resulting in contraction of the cardiac muscle. These w...
EB
Answered by Emma B. • Biology tutor
4604 Views

When is it suitable to use the 'imparfait de l'indicatif' tense?

The French imparfait of the verbs has the same use as the English past continuous: it refers to an action which was ongoing in the past until interrupted.
Answered by • French tutor
2282 Views

Make x the subject of the formula 3(2x – y) = ax – 4

Making x the subject of the formula means putting it into the form x = ..... As we can see there is an x on either side of the equation and brackets on the left side. Firstly according to BIDMAS we should ex...
JQ
Answered by Joseph Q. • Maths tutor
4600 Views

Aditi, Becky and Cali collect coins. Aditi has 6 more coins than Becky. Cali has 1 less coin than Aditi. Altogether they have 71 coins. How many coins do they each have? Show all your working.

Form 3 equations. Equation 1: A= 6+ B.Equation 2 : C= A-1. Equation 3: A+ B+ C= 71.Substitute equation 1 and 2 into 3 to get: 6+ B + B + A - 1= 71 -> 2B + A= 66 which is equation 4. Then, substitute equat...
KS
Answered by Kelvin S. • Maths tutor
7640 Views

Differentiate the equation y = (2x+5)^2 using the chain rule to determine the x coordinate of a stationary point on the curve.

Use the chain rule as this is a composite function. Let u=2x+5.So the original equation becomes y=(u)^2.Using the chain rule: dy/dx = dy/du * du/dxdy/du = 2udu/dx = 2So dy/dx= 4uSince u=2x+5, dy/dx = 4(2x+5)...
DP
Answered by Daniel P. • Maths tutor
5657 Views