Search our library of A Level questions

Top answers

All subjects

A Level

How might you distinguish between a primary and secondary alcohol?

Warm and distill with acidified pottasium dichromate. Then test with tollens reagent. The acidified pottasium dichromate will have oxidised the primary alcohol to an aldehyde, which will form a silver mir...

Answered by Zoe B. • Chemistry tutor

37609 Views

Express Cosx-3Sinx in form Rcos(x+a) and show that cosx-3sinx=4 has no solution MEI OCR June 2016 C4

Cosx-3sinx =R(CosxCosa-SinxSina) 1=Rcosa R^2=1^2+3^2 r=(10)^0.5=(approx)3.16 a=1.249 3.16Cos(x+1.249)=4 has no solution as 4<3.16 so as cos(theta) has maximum value of 1, there are no solutions

Answered by Jakub P. • Maths tutor

5279 Views

Find CO-Ordinates of intersection of 2x+3y=12 and y=7-3x

Picture of Answer available on request

Answered by Jakub P. • Maths tutor

4591 Views

Differentiate the function f(x) = (x^2 - 1)^3

Using the chain rule: f '(x) = (2x) (3) (x^2 - 1)^2 = 6x(x^2 - 1)^2

Answered by James B. • Maths tutor

3429 Views

Explain synaptic transmission at a cholinergic synapse.

A synapse is a gap between neurons that allows communication between different neurons using chemical messengers or neurotransmitters. Let's start simple and describe the...

Answered by Maaz M. • Biology tutor

8568 Views