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C3 Trig Questions

creativebuzz

This is how far I've got! Have I gone wrong somewhere?

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Reply 1

aoxa

Your division of costhetacos15.

You've canceled too much. On the first term for example; sintheta cos 15/costheta cos 15 = sintheta/costheta = tan theta, not tan theta tan15, if that makes sense.

Reply 2

creativebuzz

Original post by aoxa

Your division of costhetacos15.

You've canceled too much. On the first term for example; sintheta cos 15/costheta cos 15 = sintheta/costheta = tan theta, not tan theta tan15, if that makes sense.

Ah I've got it, thank you so much! :biggrin:

If you don't mind, can you help me on how I can do this question:

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Reply 3

davros

Original post by creativebuzz

This is how far I've got! Have I gone wrong somewhere?

I can't comment on your method, but it would have been much simpler to have divided both sides of the original equation by cos(theta + 15) to get an equation for tan(theta + 15) :smile:

Reply 4

Kevin De Bruyne

Original post by creativebuzz

Ah I've got it, thank you so much! :biggrin:

If you don't mind, can you help me on how I can do this question:

Looks like you should seperate the variables.

Reply 5

aoxa

Original post by creativebuzz

Ah I've got it, thank you so much! :biggrin:

If you don't mind, can you help me on how I can do this question:

You're welcome!

Hmmm. I'm getting deja vu - I swear we were doing this the other week! :tongue:

Again, I don't do that for my exam board, but the general solutions is when (for tan) you'll get a solution + 180n or something similar, so I'd suggest integrating by parts to get to a function, then solving from there?