May 15, 2024 · Nearly. It's equal to 2 (sinx)^2. Proof is from the double angle formula.

May 20, 2019 · I found the solutions by cancelling out the 1 - cos2x using the proof from part (a), and then finding a quadratic in tan to get the right solutions (x = pi/4 and 1.326).

Jun 11, 2024 · Edit: Oh, is that meant to be \frac {1-cos2x} {sin2x} sin2x1−cos2x, sorry. my eyeball wasn't very helpful :P Edit2: Is it supposed to be cosec2x + cot2x?, cause that works.

Jul 21, 2022 · Double angle identities are a good way to do it and youre sorted, but a couple of others. 1) Spot the answer sin (0) + cos (0) = 0 + 1 = 1 so 2x = ... Also sin (pi/2) + cos (pi/2) = 1 + 0 = 1 So 2x = .... 2) Harmonic form is when you write it in the form Rsin (2x + alpha). Fairly easily R = sqrt (2) and alpha=pi/4 (arctan (1)). So... Its useful sometimes to have a few approaches …

May 15, 2024 · Hi all, Answering an example question in the textbook and I don't understand how they get a certain answer. Attached my working below. I even used the solve function on the calculator to check if it was correct and it was, so I must be doing/entering something wrong. Can't figure out what it is. Yes my calculator is in radians before anyone asks and I'm using arcsin! …

May 15, 2024 · So where do you get 2/4 from? Use the identity sin^2 (x) + cos^2 (x) = 1, and work out whether to take the positive or the negative square root from the information you're given.

Use the double angle identity cos2x = 2cos^ {2}x -1 cos2x = 2cos2x− 1 , which you can rearrange appropriately.

Hi, I am having difficulties with this question in a paper I have just done. Using the identity (1-cos2x)/sin2x = tanx Solve, giving your answer in terms of π, 2 (1-cos2x) = tanx for 0<x<π Really appreciate your advice. I currently cannot see how to solve the equation by rearrangement.

Surely you can see that if \cos 2x = 2\cos^2 x -1 cos2x = 2cos2x− 1 then you add 1 to both sides to get \cos 2x + 1 = 2\cos^2 x cos2x+ 1 = 2cos2 x then divide both sides by 2.

1. cos5x=cos (2x+3x)---->expand that using the cos (a+b) identities 2. use the double angle identity and put cosx in terms of sinx 3.Try expanding them both and putting one in terms of the other