
Prove addition formulae using geometric construction

Visualise sin(2x) Double Angle Formulae
The double angle formulae are useful in solving trigonometric formulae.
This display allows you to view formulae relating to with an adjustable constant.
Initially, is set to 0 so you can visualise how arises as the product of and .
Then, by adjusting , and to make the green and red curves coincide, you can view the double angle formulae,
not only for , but for other values of too.
Initially,
Then, by adjusting
Visualise cos(2x) Double Angle Formulae
The double angle formulae are useful in solving trigonometric formulae.
This display allows you to view formulae relating to with an adjustable constant.
By adjusting , , and to make the green and red curves coincide, you can view the double angle formulae,
for in its different forms.
By adjusting
Visualise sin(x a) Addition Formulae
This display allows you to visualise the addition formulae:
Visualise cos(x a) Addition Formulae
This display allows you to visualise the addition formulae:
Visualise a sin x b cos x to sin
This display allows you to visualise the transformations:
After adjusting and , you can adjust and to their derived values to see the two curves coincide.
For a better view, you should use the navigation buttons in the lower right corner to zoom in and out.
After adjusting
For a better view, you should use the navigation buttons in the lower right corner to zoom in and out.
Visualise a cos x b sin x to cos
This display allows you to visualise the transformations:
After adjusting and , you can adjust and to their derived values to see the two curves coincide.
For a better view, you should use the navigation buttons in the lower right corner to zoom in and out.
After adjusting
For a better view, you should use the navigation buttons in the lower right corner to zoom in and out.