17. Trigonometric equations 2. Additional Maths OCR FSMQ

[@mahkal1357]

you make it so easy. thank you

[@varshniesriharan2766]

these videos are great and so helpful !

[@bareaumaths]

I'm really glad they're helpful. Please spread the word!

[@akivuppalanchi7368]

Thank you so much for this!!

[@bareaumaths]

My absolute pleasure.

[@doubletrouble4815]

Sir, is it ok if I round my values for 2x before dividing them by 2? Or should I leave them un rounded until the end?

[@bareaumaths]

Try to avoid rounding until the end.

[@rayyanchan9593]

Hi Sir, just a quick question. In the exam questions like tan(2x) = 0.5 can come up and to answer these type of questions you let 2x equal theta and you change the boundaries e.g. 0≤x≤90 becomes 0≤2x≤180. What I wanted to know could questions like sin(X + 30) come up in the add maths exam, and if so am I correct in saying once you have equaled to theta, if the boundaries were 0≤x≤90 they'd become 30≤ x+30 ≤ 120 Sorry to bother. Thanks!

[@bareaumaths]

Sounds like you understand the topic very well! Yes - do exactly as you said.

[@rayyanchan9593]

Thankyou very much sir :)

[@SH-eo2py]

Hello could you PLEASE make a video on this topic but with the CAST circle instead of the graohs pls im so desperate your vids are saving me rn

[@bareaumaths]

No time, sorry (And I am not a fan of CAST). Good luck on Friday!

[@Igeorgl]

Hi, If I had an equation to solve like sin^2(x)= 0.75, for 0 to 360, how would I go about doing that as using the CAST method I can only find the first two values, 60 and 120?

[@bareaumaths]

If Sin^2 (x) = 3/4 then Sin (x) = root3/2 or Sin (x) = - root3/2 Then find the solutions for each (which should be 60 and 120 for the first equation, and then 240 and 300 for the second). Does that help?

[@Igeorgl]

@@bareaumaths thank you! Yes, I was a bit confused on the CAST method itself but I now feel more comfortable, your videos are very helpful as always👍

[@wiktorlis6380]

Hi sir, just wanted to ask a quick question. for the questions, in which there is 2x involved, like for example tan(2x) = 0.5, can we also using the double angle formulae (tan(2x)=2tanx divided by 1-tan^2x ? and then manipulate the equation to something solvable then sketch the tanx graph to obtain our solutions?

[@bareaumaths]

Yes... But that would be over-complicating things a great deal, and take a lot more effort! You don't need the double angle formulae in the add maths course - so if you're tempted to use them, think to yourself that there's probably a simpler way.

[@jackyellow8562]

is theatre always 0?

[@bareaumaths]

Theta (the greek letter which denotes the unknown angle) can be any value from negative infinity to positive infinity.

[@jackyellow8562]

@@bareaumaths At 13:40 you didnt include x as equaling 0 but in the previous worked example 10:19 you included theta as equalling 0

[@bareaumaths]

@@jackyellow8562 In the previous question, zero was a solution but not in the one at 13:40.

[@bareaumaths]

Cos(theta)=1 has solutions of 0, 360, etc

[@bareaumaths]

Sin(theta)= -1 has solutions at 270, etc, but not at zero