Given the recurrence relations f_0 = c and f_… | GMAT Sprint

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sub-505

Functions

Given the recurrence relations $f_0 = c$ and $f_n = f_{n-1} + d$ for all n > 0, what is the value of $f_3$ when c and d are constants?

Answer Choices

Correct answer marked below

c + 3d

Correct

c + d^2

c^2 + d

c^2 + cd

c^2 + cd + d

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Explanation

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Official Explanation

Official

Starting with [m]f_0 = c\ \ f_1 = f_0 + d = c + d\ \ f_2 = f_1 + d = c + d + d = c + 2d\ \ f_3 = f_2…

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Comments

MuditNov 14, 2024

thanks

ElaAug 6, 2024

thanks a lot

AbdullahOct 3

thanks, this one was easy once I remembered f_0 is just the starting value

VigneshAug 24

wait is f_0 really c? I kept trying to plug in n=0 for some reason lol

KartikAug 27

yeah f_0 is given directly, you only use the recurrence for n>0

VanessaMay 14

Just add d three times to c and you're done. Sub-505 for sure.

HarshSep 23

the answer choices with d^2 and c^2 are such traps, easy to overthink this

What this question tests

What it tests

Your ability to evaluate and compose functions, including unusual defined operations.

Common trap

Applying function operations in the wrong order or ignoring domain restrictions.

Given the recurrence relations f0=cf_0 = cf0​=c and fn=fn−1+df_n = f_{n-1} + dfn​=fn−1​+d for all n > 0, what is the value of f3f_3f3​ when c and d are constants?