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the key thing is using concept of toa cah soh
Date Posted:
3 years ago
thankyou
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using pythagoras theorem to find cos2A, 2A as the angle. not sure if it’s correct, hope that it’s helpful!
Date Posted:
3 years ago
But then if 45 < A < 90, then it follows that 90 < A < 180 so 2A is a second quadrant angle, so cos 2A will have a negative value (after Pythagorean Theorem is applied)