Four Muffins
New member
- Joined
- Jun 29, 2022
- Messages
- 25
Hello. I'm trying to prove trig identities, and I've gotten stuck on question 57 because I don't know how, or if I can, deal with a triple angle with what I have available. I realise I could probably solve it by Googling the triple angle formula, but I think that is not the intent of the exercise. I don't yet know how to derive the addition formula to get at the double or triple angle formula, and the exercise for that is 30 questions ahead of me.
I suspect I'm supposed to be able to solve this with what I've done so far, but I'm unsure. Either way, I've tried a bunch of times and always get stuck at either turning the right side into a triple angle, or turning the triple angle into something else.
I included the textbook material and previous questions for context.
These identities come with explanations, I chopped them out for space. The rest of the trig section is the functions and their graphs. It's only eight pages all up.
The question I'm stuck on is 57. I haven't tried 58 yet, but I will have the same problem I bet.
My latest two attempts. They all end in the same spot, with me trying a different way to manipulate [imath]cos^2(theta)[/imath]. I don't see another point at which to attack the problem after rewriting [imath]sin(2theta)[/imath]
I suspect I'm supposed to be able to solve this with what I've done so far, but I'm unsure. Either way, I've tried a bunch of times and always get stuck at either turning the right side into a triple angle, or turning the triple angle into something else.
I included the textbook material and previous questions for context.
These identities come with explanations, I chopped them out for space. The rest of the trig section is the functions and their graphs. It's only eight pages all up.
The question I'm stuck on is 57. I haven't tried 58 yet, but I will have the same problem I bet.
My latest two attempts. They all end in the same spot, with me trying a different way to manipulate [imath]cos^2(theta)[/imath]. I don't see another point at which to attack the problem after rewriting [imath]sin(2theta)[/imath]