OK, squaring and rearranging so everything contains either cos^2 x or sinxcosx will let you use a cos(2x + a) type expansion on it and solve. I can't believe this would be taught as a practical technique though - you're making the problem more difficult just to go back and solve it in a different way!(Original post by bryan966)
Hey there. This is what my mom's colleague got. I'm a bit confused whether is a valid solution. A lil warning tho, it takes time to know which part comes first. Cheers
Also, when you square an equation you have to make sure you don't generate any spurious solutions e.g. if you start with A = 4 then A^2 = 16, but the second equation would also be solved by A = -4.
Need help with this trigonometric question involving r cos(2x + a). Confused Watch
- Study Helper
- 21-07-2014 10:16
- 20-05-2016 11:09
there s wrong working at blue line. the expansion din complete
- 20-05-2016 19:27
The question in that form just seems kind of pointless. The point of this technique is to allow you to isolate x by writing the original equation in terms of one trig function which then can be inverted.
This Q is like saying here is a question with a standard solution technique but we want you to do something obscure and pointless.
Hence, it is almost certainly a misprint or typo of some kind.