If the coefficient of $(2 r + 4)^{t h}$ and $(r - 2)^{t h}$ terms in the expansion of ( $1 + x)^{18}$ are equal, then r =

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

Open in App

Solution

The correct option is D
6

$^{18} C_{2 r + 3}$ = $^{18} C_{r - 3}$ ⇒ 2r + 3 + r - 3 = 18 ⇒ r = 6

Suggest Corrections

Similar questions

If the coefficient of $(2 r + 4)^{t h}$ and $(r - 2)^{t h}$ terms in the expansion of ( $1 + x)^{18}$ are equal, then r =

(2 r + 4)^{t h}

(r - 2)^{t h}

(1 + x)^{18}

r

(1 + x)^{18}

=

r

(2 r + 4)^{t h}

(r - 2)^{t h}

(1 + x)^{18}

{(2 r + 4)}^{t h}, {(r - 2)}^{t h}

{(1 + x)}^{18}

Join BYJU'S Learning Program