Question

In the figure, O is the centre of the circle. If the diameter AOB rotates about O, which of the following is/are constant?
I. θ+Φ
II. AC+BD
III. AC*BD

Answer 1

What is your attempt ?

Answer 2

?

Answer 3

Have you tried the ques?

Answer 4

i just only know θ+Φ is correct..

Answer 5

Yep,
II is also correct of course.

Answer 6

why?

Answer 7

If one arm goes up by, say x units, then other arm goes down by x units, right?

Answer 8

yup

Answer 9

So sum = const.

Answer 10

For III, lets take a case when both are equal.

Answer 11

yes

Answer 12

If one goes up by x, its length = h+x
other goes down = h-x

product = h^2- x^2

product earlier = h^2

both products are diff

Answer 13

ohhh i got it, that means III is wrong

Answer 14

Am glad you got it!

Answer 15

thank you very much:)