Question

Find the value of Sin(2sin-1(o.8))

Answer 1

0.8 is same as 8/10=4/5

Hence sin-1 (o.8) will be

sin-1 (4/5) =53 degree appprox

Answer 2

2sin-1(4/5)=53*2

Answer 3

So your question reduces to

sin(53*2)=....

Answer 4

How did you get 53*2 ?

Answer 5

sin-1 (4/5) =53

2sin-1 (4/5) =2*53

Answer 6

Am sorry but I dont understand.
How did you get 53 in the first place ?

Answer 7

Its elementary right triangle. The values are knowledge based.If you don't know that then use a calculator.

Answer 8

Actually is there any other method ?
we're not supposed to use calculators.

Answer 9

okay use the elementary triangle

Answer 10

This is knowledge based data.You should keep this triangle in your mind.