Law Yun Zhi's answer to Christine 's Secondary 4 A Maths question.

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Law Yun Zhi
Law Yun Zhi's answer
2 answers (Tutor Details)
Here is the solution. Essentially you need to take (x-50) as a variable. Then, you need to get the range for (x-50). After that, when you solve for cos^(-1) (-0.25), you list down all solutions that fall in that range.
3 years ago
Because the answer should be 0,90,180 and 360