Search our library of homework questions

Top answers

All subjects

All levels

Using the identity cos(A+B)= cosAcosB-sinAsinB, prove that cos2A=1-2sin^2A.

Use cos(A+B)=cosAcosB-sinAsinB and let A=B so cos(A+A)=cosAcosA-sinAsinA this means cos(2A)=cos²A-sin²A and since cos²A+sin²A=1, cos²A=1-sin²

Answered by Rebecca F. • Maths tutor

20242 Views

How can you distinguish between the different cadences?

The first step is to decide whether the extract sounds complete or not. If the extract sounds completed, it will either be a perfect or plagal cadence. The chord progression of a perfect cadence is V-I. T...

Answered by Samantha B. • Music tutor

6234 Views

Describe the events that occur at synaptic junction that result in an action potential in the post synaptic membrane.

An action potential arrives at the pre synaptic membrane which initiates the opening of Ca2+ channels. The influx of Ca2+ ions will cause vesicles containing neurotransmitters to fuse with the pre-synapti...

Answered by Samantha B. • Biology tutor

3255 Views

Outline the major stages of cell cycle.

The cell cycle is comprised of two distinct phases; Interphase and Mitosis. The cell is typically in interphase of 95% of its life and mitosis/division for the remaining 5%.During interphase the cell's nu...

Answered by Max K. • Biology tutor

3073 Views

A rectangular hyperbola has parametric equations x = 4t, y = 4/t , (z non 0). Points P and Q on this hyperbola have parameters t = 1/4 and t = 2. Find the equation of the line l which passes through the origin and is perpendicular to the line PQ.

Since we are told that the line l is perpendicular to the line PQ, we first need to find out the gradient of PQ.
To do this, it is easiest to find out the co-ordinates of points P and Q in terms of...

Answered by Zelie E. • Further Mathematics tutor

2178 Views