Qualification > Math

doubt in finding angles!

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masterof13:
i have a huge problem when it comes to finding the second angle of an equation like this for eg cos(x-73.4)=3/5 ???
the first angle is easy to find but i really need help to find the second angle, can anyone give me a step by step solution?
thanks alot!!!
masterof13

falafail:

--- Quote from: masterof13 on May 25, 2010, 01:19:22 pm ---i have a huge problem when it comes to finding the second angle of an equation like this for eg cos(x-73.4)=3/5 ???
the first angle is easy to find but i really need help to find the second angle, can anyone give me a step by step solution?
thanks alot!!!
masterof13

--- End quote ---
well at first you obviously have to cos-1 3/5, so you get an angle right?
since this is cosine and +ve, you also do 360 - the angle

remember, CAST

in the first quadrant, sin cosine and tan are all +ve.
in teh second quadrant, sin only is +ve. (you do 180 - the angle)
in the third quadrant, tan only is +ve. (180 + the angle)
in the fourth quadrant, cos only is +ve. (360 - the angle)

so if you get a +ve angle with sin for example, your answer would be that angle, and 180 - the angle.
if you get a +ve angle with tan, your answer would be that angle, and 180 + the angle.

also, any angle + 360 is the same angle, but usually you don't have to do that because it's not in the range.

i hope this helps. feel free to ask me if you still have any questions. :)

masterof13:
WOW!! Thanks this helped so much!!
i actually forgot the CAST rule!!
thank you very very much!! ;D

falafail:

--- Quote from: masterof13 on May 25, 2010, 01:38:45 pm ---WOW!! Thanks this helped so much!!
i actually forgot the CAST rule!!
thank you very very much!! ;D

--- End quote ---

you're welcome :)

dodo:
plzzzzzzzzzzzzzzzzz hlep question 9 in jan 2010 part a pllzzzzzzzzzzzzzzzzzzzzzzzzz how to get x from 6x^-0)5 -3/2x^0)5 plzzzzzzzzzzzzzzzzzzzzzzzzzzzz

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