1not jee level !!
Q)A person standing on the bank of a river observes that angle of elevation of the top of the tree on the opposite bank of the river is 60° and when he retires 40m away from the tree the angle of elevation becomes 30°.The breath of river is
a)40m
b)30m
c)20m
d)60m
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8 Answers
1h (ht. of the tree) = x
cotθ1 - cotθ2
substituting,
h = 40
cot60 - cot30
h = 40√3 / 2 = 20√3m
now find out the breadth by applying tan60.
62what do you guys mean
It can be the doubt of any user... and everyone is not as good as every other user...
Please dont post messages that can bring down people's confidence....
Just because you can solve it easily does not mean that you comment like that.. Please keep in mind that it seriously hurts the confidence of other users.. and that if you find it too easy just ignore...
Your comments in such respect is not welcome...
1this is question from 2004 aieee..........i cn also give u question no. if u want................so better think before saying anything
11
\frac{H}{W} = \sqrt{3} ........................(1)
\frac{H}{W+40} = \frac{1}{\sqrt{3}} .........................(2)
From (1) & (2)
3W = W+40 \Rightarrow W = 20
