Question

A stone is thrown vertically upward from the top of a tower of height 24.5m with an initial velocity of 19.6 m/s. Calculate :- ➻ (a) the height to which the stone will rise before returning to the ground ➻(b) the velocity with which it will strike the ground ➻(c) the total time of its journey.​

Answer 1

Answer:

Coefficient of x⁶y³ is 672.

Step-by-step explanation:

General term of expansion (a+b)ⁿ is

\bf \: T_{r+1} = \: \: ^nC_r \: \: \large \frak{ a ^{n−r} b ^r}T

r+1

=

n

C

r

a

n−r

b

r

For (x+2y)⁹,

Putting n =9, a=x, b=2y

\begin{gathered} \bf \: T_{r+1} = \: \: ^{9} C_r (x) ^{9−r} (2y) ^r \\ \\ \bf \: T _{r+1} = \: \: ^{9} C_r (x) ^{9−r} .(y) ^r .(2) ^r\end{gathered}

T

r+1

=

9

C

r

(x)

9−r

(2y)

r

T

r+1

=

9

C

r

(x)

9−r

.(y)

r

.(2)

r

Comparing with x⁶ y³ , we get, r = 3

T

r+1

9

C

3

(x)

9

−3.y³.2³

9!(2)³×x⁶×y³)/(3!.6!)

672x⁶y³