Questions 11-13, thanks for reading and I hope someone can help
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Trig Identities C2 Help - no idea how to do these questions, need help ASAP. watch
- Thread Starter
- 31-10-2015 17:47
- 31-10-2015 18:43
Question 11 seems a bit vague to me, and I'm not confident with my answer but I just did this:
Let's just say theta = x for simplicity
sinx = p/3 and cosx = q/7
arcsin(p/3) = arccos(q/7)
For twelve, I suggest you follow a similar method to what I've done above. Rearrange the two equations to make them equal to k, then manipulate the two equations to find theta. Using theta you can find k.
For question 13, expand the left hand side of the two equations using the addition and double angle formulas respectively.
You can use the expansion of cos2x = 0.5 to find an exact value for either sin x or cos x depending on which you use, then sub that into the expansion of the other equation.
This is C3, by the way. Was that a typo or did you think these were C2 questions?
Last edited by 16Characters....; 31-10-2015 at 19:02.
- 31-10-2015 18:56