Q. If f(1)=7 and f(n+1)=−3f(n)−4 then find the value of f(4)Answer:
Find f(2): Use the given recursive formula to find f(2). We know that f(1)=7. The recursive formula is f(n+1)=−3f(n)−4. Substitute n=1 into the formula to find f(2). f(2)=−3f(1)−4f(2)=−3(7)−4f(2)=−21−4f(2)=−25
Find f(3): Use the recursive formula to find f(3). We now know that f(2)=−25. Substitute n=2 into the formula to find f(3). f(3)=−3f(2)−4f(3)=−3(−25)−4f(3)=75−4f(3)=71
Find f(4): Use the recursive formula to find f(4). We now know that f(3)=71. Substitute n=3 into the formula to find f(4). f(4)=−3f(3)−4f(4)=−3(71)−4f(4)=−213−4f(4)=−217
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