Question

Find the sum of the first 10 terms of an AP whose n terms is 2n-3/6

Answer 1

Answer:

$\pink{ A(x_1,y_1) \: and \: B(x_2,y_2)}$

$\purple{\bf \:( x, y) = (\dfrac{x_1+x_2}{2} , \dfrac{y_1+y_2}{2} )}$

$\begin{gathered}\Large{\bold{\pink{\underline{CaLcUlAtIoN\::}}}} \end{gathered}$

$\sf \:( x, y) = (\dfrac{x_1+x_2}{2} , \dfrac{y_1+y_2}{2} )$

$\bf \:x_1 = - 1 ,y_1 = - 12,x_2= - 1 ,y_2=4x$

$\bf ( x, y) = (\dfrac{ - 1 - 1}{2} , \dfrac{ - 12 + 4}{2} )x,y)$

$\bf ( x, y) = ( - 1 , - 4)(x,y)$

Answer 2

Answer:

Answer

S

n

=2n

2

+3n

We know that nth term of AP is given by

a

n

=S

n

−S

n−1

⟹a

n

=2n

2

+3n−2(n−1)

2

−3(n−1)

⟹a

n

=4n+1

Tenth term=a

10

=4×10+1

⟹a

10

=41