Trigonometric
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Diagram shows a L-shaped rod ABC where angle ABC = 90 deg, AB = 80 cm and BC = 60cm. It is hung from the ceiling at B such that CB makes an angle of deeter(?) with the ceiling. Points P and Q are 2 pointes on the floor which are vertically below A and C respectively. Given that deeter(?) varies,
state the range of PQ.
the (?) refers to spelling uncertainty. thanks.
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u mean theta.
min value is 60
max value is sqrt(60^2+80^2) = 100.
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why is the minimum value 60?
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"State" means no working is necessary.
Minimum occur when BC is against the roof, answer 60.
Maximum occur when AC parallel to PQ, answer 100.
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Nope, there is a definite method for this question. HintL Compare sin and cos graph. When sin graph is a maximum, cos graph is a minimum. From here, you can sub in the necessary values.
Eg. 80(0) + 60 (1) = 60 (minimum)
80(1) + 60(0) = 80 (cannot be minimum)
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Originally posted by anpanman:
Nope, there is a definite method for this question. HintL Compare sin and cos graph. When sin graph is a maximum, cos graph is a minimum. From here, you can sub in the necessary values.
Eg. 80(0) + 60 (1) = 60 (minimum)
80(1) + 60(0) = 80 (cannot be minimum)
1st, we know that there is a definite method. However the question only ask for the answer and not the workings. So jay and me... just state as per the requirements of the question.
In addition,your suggested method defeated the purpose of learning the R formula. The appropriate technique to use here is the R formula.