What is the first step to prove that Sn1 + 5 + 9 + ... + (4n - 3) = n(2n - 1)? a.
Verify that Sn is valid for n = 1. A is the Answer
c.
Assume that Sn is valid for n = k
b.
Show that Sn is valid for n = k
d.
Prove that Sn is valid for n = k + 1

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?