Skip to content
MathsGenie logo
Open app

Course home

  1. A Level
  2. Maths WJEC
  3. Question bank

Trigonometry and Modelling

EasyMediumHard
1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980
Question 14

A mathematician is verifying a table of trigonometric identities for the variable α\alphaα.

a.

Using the compound angle identity for sin⁡(A+B)\sin(A + B)sin(A+B), derive the identity for sin⁡2α \sin 2\alpha\,sin2α in terms of sin⁡α \sin \alpha\,sinα and cos⁡α\cos \alphacosα.

[2]
b.

Using the compound angle identity for cos⁡(A+B)\cos(A + B)cos(A+B), derive the identity for cos⁡2α \cos 2\alpha\,cos2α in terms of sin⁡α \sin \alpha\,sinα and cos⁡α\cos \alphacosα.

[2]
ci.

Hence, write cos⁡2α \cos 2\alpha\,cos2α as an expression containing only the term cos⁡α\cos \alphacosα.

[2]
cii.

Hence, write cos⁡2α \cos 2\alpha\,cos2α as an expression containing only the term sin⁡α\sin \alphasinα.

[2]
d.

Utilize the addition formula for tan⁡(A+B)\tan(A + B)tan(A+B) to find an expression for tan⁡2α \tan 2\alpha\,tan2α in terms of tan⁡α\tan \alphatanα.

[2]

Trigonometry and Modelling Questions

  1. A Level
  2. /Maths
  3. /Trigonometry and Modelling