Question

30th term of AP 10, 7, 4...is

Answer 1

Given Ap=10, 7, 4

Here,

a=10

d=7-10=-3

So 30th term

=10+(30-1)×(-3)

=10+29×(-3)

=10-87

=-77

Answer 2

30th term of AP 10, 7, 4...is

Solution -

$a = > 10 \\ \\ d = > a2 - a1 \\ \\ d = > 7 - 10 \\ \\ \boxed{d = > - 3}$

$\boxed{ \underline \bold \red{an = > a + (n - 1) \times d}}$

$a30 = > 10 + (30 - 1) \times - 3 \\ \\ a30 = > 10 + 29 \times - 3 \\ \\ a30 = > 10 - 87 \\ \\ \boxed{a30 = > - 77 }$

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Other important formula

$\boxed{ \underline \bold \blue{sn = > \frac{n}{2}(2a + (n - 1) \times d) }}$

This Formula is required whenever sum of AP series' is need to calculate .

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