Question

plzzz help.....plzzzz...♥✌✌​

Answer 1

Answer:

(1)50

(2)9

(3)B

(6)3

(7)

Answer 2

1)sim(90-a)=cosa=cos 40°

so a=40

2) simply put the value in the given eqaution

on putting u will get 9 as answer

3)in the series,chapter u had dervied a formula ,for the sum of n natural number starting from 1=n(n+1)/2

4)i^9+i^19=i^8×i+i^16+×i^2×i^1. (we know that i^4n always eqaul to 1)

=i-i

=0

so,a+ib=0

which shows,a=0 and b=0