Question

give me important case study based questions class x
of maths

also wish me to get good marks in today's exam​

Answer 1

Answer:

Q. The first and the last terms of an AP are 10 and 361 respectively. If its common difference is 9 then find the number of terms and their total sum?

Sol.

Given, first term, a = 10

Last term, al = 361

And, common difference, d = 9

al = a + (n −1)d

361 = 10 + (n − 1)9

361 = 10 + 9n − 9

361 = 9n + 1

9n = 360

n = 40

Therefore, total number of terms in AP = 40

Now, sum of total number of terms of an AP is given as:

Sn = n/2 [2a + (n − 1)d]

S40 = 40/2 [2 x 10 + (40 − 1)9]

= 20[20 + 39 x 9]

=20[20 + 351]

=20 x 371 = 7420

Thus, sum of all 40 terms of AP = 7420

Answer 2

Answer:

it's trigonometry

can I have introduction plz

have a nice day