The horizontal distance x and vertical distance y in feet travelled by a firework can be calculated by
the functions x(t) = v(cos )t and y(t) = 16t2 + v(sin )t. In these functions, v is the initial velocity of
the firework, is the angle at which the firework is launched, and t is the time in seconds. A firework
is launched with an initial velocity of 166 ft/s at an angle of 60. To achieve the greatest effect, the
firework should explode when it reaches its maximum height. Approximately how long after the
launch should the firework explode?
OPTIONS
1) 2 s
2) 12 s
3) 13 s
4) 15 s
5) 4.5 s



boss y component of velocity must b zero at highest point..
dy/dt=0
so velocity in y direction shud b =0
v(y)=-32t+vsin60
v(y)=0
t=4.5second.....5 option
:)

i got :
f(a,b) = (a + b -1 - no. of common factors except 1)
take any value for this :
like (2,1) :
f(2,1) = (3-1) = 2
for (3,2) :
f(3,2) = (3+2-1) = 4
similarly,
for (343,56) :
f(343,56) = (343 + 56 - 1 - 1)
= 397
pls explain..
f(343,56)=(343+56-hcf(343,56))=392

392....we can use equation of line and with some approx....it is find that fr every value of y...7 unit sq r cut on x axis...:)

@kunal : is the question correct??
@krazy : If kunal says yes then pls solve it. i think i m not getting it by ur method.

Ram has five boxes of different weights having integer values, between 53 and 100 kg. But he cannot weigh these boxes as all the available weights are more than 100 kg. So, he weighs all the possible pairs of boxes and gets 10 weights as 110, 112, 113, 114, 115, 116, 117, 118, 120 and 121 kg. find min and max weights. (practice prob for the just discussed concept.)
4 numbers has to b even and one to b odd...
answer:54,56,58,59,62

Originally Posted by Angadbir
What is the largest possible number of elements in a subset S` of S = {1, 2, 3, ... , 9} such that the sum of every pair of distinct elements in S` is different
a. 4
b. 5
c. 6
d. None of these
ans is 5(1,2,3,9,5)

this article strongly predilects towards our goal