Help maths urgent 😭

I don’t get how to do this, on the markscheme how do they do they get the first line??
Do they use double angle formula for this

part b
I got this

(edited 11 months ago)

Reply 1

davros

Original post by Alevelhelp.1

I don’t get how to do this, on the markscheme how do they do they get the first line??
Do they use double angle formula for this

part b
I got this

That looks like the mark scheme for a completely different question :smile:

Reply 2

Alevelhelp.1

Original post by davros

That looks like the mark scheme for a completely different question :smile:

It’s actually not 😂 idk why it’s wrong 😑
Anyways can u help with this q
I don’t het how I know if to make the R…
an Rcos(theta plus alpha) or an Rsin(theta plus alpha)

Reply 3

davros

Original post by Alevelhelp.1

It’s actually not 😂 idk why it’s wrong 😑
Anyways can u help with this q
I don’t het how I know if to make the R…
an Rcos(theta plus alpha) or an Rsin(theta plus alpha)

It's entirely your choice. If you find things confusing, then it's probably best to stick to one version e.g. Rsin(theta + alpha) and use that all the time. things will sort themselves out when you do the actual working :smile:

Reply 4

Alevelhelp.1