5R/3

m sorry answer is 5R/3

3R/5

definitely 5%

hey i saw one of the replies u got bt i think u need sum of n terms in arithmogeometric progression.if it is then u can use the following technique.

first identify the common ratio of the agp.for example in the following series of agp,

5+21+81+297......

the series can be written as 5*1+7*3+9*9+11*27.......

in this series common ratio of the agp=3

S=5*1+7*3+9*9+11*27

3S=     5*3+7*9+9*27......

subtracting n taking the common difference of the ap common, u get

-2S=5*1+2(3+9+27+81+.......)

n u can find the sum by applying the formula for sum of gp obtained in brackets.substitute the value of n correctly.did u get it?

frnds -CH3 group can also show +R effect through hyperconjugation effect.in Ph-CH3,CH3 is attached to a C which is directly attached to CH3 has vaccant p orbital n 3 alpha CH bonds.so through hyperconjugation C in CH3 takes electrons from H, which result in bond fission on double bond. as a reut ressonating structures can be formed.

Ph-(C=0)-CH2-C=0-0Et is more stable.in tautomerism enols and aldehyde/ketones exist in state of dynamic equilibrium.enols are more stable only in case of aromatization or hydrogen bonding.on tautemerism both show hydrogen bonding while 1st only shows aromatization.so first wil have higher enol concentration.

mgcot theta whole divided by 2

oyee since F=dp/dt so F=d mv/dt here velocity is constant n mass is variable so in this case a = dm/dt so a=0.2 so v=20+0.2*10=22m/s

oyee since F=dp/dt so F=d mv/dt here velocity is constant n mass is variable so in this case a = dm/dt so a=0.2 so v=10+0.2*10=12m/sans

it must be 300 times.consider 0-99.in this 3 appears 10 times 10C1 n times at tens place 10C1. 3s being identical there permutations will b =2!/2!=1.thus no.of ways = 10+10=20.similarly for 100-199,200-299,400-499,500-599,600-699,700-799,800-899,900-999. for 300-399,3 appears 100 times at 100s place n 10 times each at 10s n 1s place.thus total no.of ways =9*20+100+20=300ans