Search our library of A Level questions

Top answers

All subjects

A Level

The equation x^3 - 3*x + 1 = 0 has three real roots; Show that one of the roots lies between −2 and −1

In order to prove that one real root of an equation is situated in a certain interval, we calculate the value of the function at the ends of the given interval. In the given case, f(-2) = (-2)^3 - 3*(-2) ...

Answered by Paul T. • Maths tutor

11927 Views

y=4x^3+6x+3 so find dy/dx and d^2y/dx^2

dy/dx=12x^2+6 d^2y/dx^2=24x

Answered by Swapnil P. • Maths tutor

5156 Views

How useful are these sources for our understanding of Nazi Germany from 1933 to 1939? (32 mark)

There are many aspects which contribute to our understanding of Nazi Germany within the period of 33-39. Within source A we are prevented with a satirical cartoon which grates harshly upon the regime of t...

Answered by Kate M. • History tutor

3766 Views

The straight line L1 passes through the points (–1, 3) and (11, 12). Find an equation for L1 in the form ax + by + c = 0, where a, b and c are integers

When finding the equation of a straight line there are two important figures to calculate. The first being the gradient (the slope of the line) and the second being the y intercept (where the line crosses...

Answered by Ruby B. • Maths tutor

19789 Views

Why are the theoretical and Born Haber lattice enthalpies different?

The theoretical Born Haber enthalpy assumes a perfect ionic model where the attraction between the ions is purely electrostatic and the ions are purely spherical. The Born Haber lattice enthalpy is the re...

Answered by Amit V. • Chemistry tutor

9047 Views