this is the most clear and concise explanation of this topic i have found. Coming from someone who isnt doing great at this topic, this video is great, thanks😁
9:23 The question was (I'll use 0 as a representative of theta) Solve the equation sin0 + cos0 = 0 You rearranged the formula so you got sin0/cos0 = -1 The completed the rearrangement by turning sin0/cos0 into tan0. So you ended up with tan0 = -1 To get 0 on it's own you formed the formula 0 = tan-1 (-1) I get all of that. What I don't get is why you used the sin equation (180 - x) instead of the tan equation (180 + x) to get the values, seeing as Tan is the only one there, and not sin. Would the values not be: x = [45] and [225]
I highly recommend watching my video on the unit circle: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4tQX198STxM.html it seems like you are getting confused at the last step of finding values of theta, which involves interpreting the final trig equation (eg tanx=-1) and understanding in which quadrant those angles will be.
I have a question, answer would be very helpful. Why do we not have 6 answers in last exercise, isn't it that cosine has the same value for two different angles? Cos(20°) is the same as cos(340°) so why isn't 340° also one of the answers?
Why in the 2nd problem of level 2 equations didn't you simplify the term (1-cosA ) Because we can rewrite 2(1- (cosA)^2) as difference of squares and on right-hand-side we can get the same with 3(1-cosA) and then we will get only 1 solution. But how it is possible?
This works fine. I suppose you are dividing both sides by 1-cosA? This is only possible if cosA =/= 1. Then you need to check if cosA=1 is a solution, which it is. So you will get the same answer :)
You could try it. Generally the t formula is used when it will be more efficient than other methods. I don’t think it would be helpful in these examples as it is possible to see a clear method available but you could try and see if it gives faster solutions. Also, this video was made for A-level maths where we don’t use the t formula yet, so if you want harder problems I recommend looking at some further maths problems :)
yes ofc just write t=sinx or t=cosx ,and rewrite the equation with t like: sinx^2+sinx-2 "(t=sinx)" rewrite it as: t^2+t-2 then lets say the t is equal to -1,1/2: write sinx=-1 and sinx=1/2 then solve the trigonometry for both sinx but remember sinx and cosx must ="-1
you need to understand how to factorise quadratic equations before trying that problem: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-1aq6N9wzP8s.html
I do not manually place the ad breaks, I just turn them on. I don’t know why there are so many ads. If you suggest I should turn off all ads then I will consider it. I’m just not sure how I could continue with RU-vid. But please let me know: no ads or just less ads? Thanks, and sorry for the inconvenience.
