Top answers

Describe the shape of and bonding in a molecule of benzine. Explain why benzene doesn't readily undergo reactions.

Flat 6-membered ring with 6 carbons. Each carbon in bonded two 1 hydrogen and 2 other carbons. Because a carbon must always have 4 bonds, there is a delocalised fourth electron on each carbon, which moves ar...
MZ
Answered by Michal Z. • Chemistry tutor
3639 Views

The new reading for James' electricity bill is 7580, and the old reading is 7510, the price per unit is 13p, how much does James have to pay for his electricity?

This question is tricky/unfair because you need to understand how meters work. The old reading was the last time the electricity bill was paid for, so the first thing you need to do is 7580-7510= 70. So that...
MZ
Answered by Michal Z. • Maths tutor
3468 Views

Solve simultaneously 2x + 3y = 18 and y = 3x – 5 to find the value of x and y.

sub the y value into the first eqn 2x + 3(3x-5) = 18 expand the brackets 2x +9x-15 = 18 add up the x values 11x -15 = 18 add 15 to both sides to cancel it out on the l.h.s 11x = 33 divide by 11 to get value ...
JG
Answered by Jessica G. • Maths tutor
4331 Views

Given that x = cot y, show that dy/dx = -1/(1+x^2)

Identify that we are looking at dy/dx, not dx/dy and realise the relationship that dy/dx=1/(dx/dy)2)Try find dx/dy;cot = 1/tan or (tan) -1 Hence, x=(tan y ) -1 implying dx/dy = (-1)(tan y) -2 (sec 2 y ) =(-1...
JF
Answered by Jacob F. • Maths tutor
12968 Views

Work out the gradient of the tangent to the curve (y=x^2-x-2) at the point where x=2

y=x^2-x-2y=(x+1)(x-2)The gradient (dy/dx) measures the rate of the change in y with respect to x. So this can be used to help us find the gradient of a function at any point along it. The question asks the t...
OG
Answered by Oriane G. • Maths tutor
5035 Views