Question

The 21st term of AP whose first two terms are – 1 and 2 is:​

Answer 1

Answer:

follow the attachment

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Answer 2

Answer:

59

Step-by-step explanation:

1st term of an AP is -1=a1

2nd term of an AP is 2=a2

common difference d=a2-a1=2-(-1)=3

therefore,21st term=a+(n-1)d

                               =a+20d

                               =-1+20(3)

                               =-1+60

                                =59

∴a21=59