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C3 edexcel chp6 ex 6e q5 help!!!

does anyone get the question and understand the solution... please help
arcsin(k)=α arcsin(k) = \alpha

sin x = k , so take the inverse , so that x = arcsin k , but arcsin k = α \alpha , so one solution is x=α x = \alpha. Now find the other positive solution using a quadrant diagram or graph to help.
Original post by NotNotBatman
arcsin(k)=α arcsin(k) = \alpha

sin x = k , so take the inverse , so that x = arcsin k , but arcsin k = α \alpha , so one solution is x=α x = \alpha. Now find the other positive solution using a quadrant diagram or graph to help.


ohhh ok, i understand how to get the 1st solution but i don't get why the 2nd solution is pi - alpha

Because it is in the 1st quadrant between 0 and pi/2
(edited 7 years ago)
Original post by ilovemaths2017
ohhh ok, i understand how to get the 1st solution but i don't get why the 2nd solution is pi - alpha


Since k is positive then arcsin k is positive, so alpha is positive and alpha must be less than 1, so the other positive solution is pi - aplha.

Think about the quadrant diagram or the sine graph if you prefer, when working out the solution to x = arcsin(constant), another solution is pi - principal solution.

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