Question

sin A=0.4 find cos2A​

Answer 1

Step-by-step explanation:

Sin A = 0.4 {Arc___= ____^ -1)

Arc Sin A= Arc Sin 0.4

A= Sin (0.4) ^-1

A= 143.24

Cos 2 (143.24)=0.2836

Answer 2

The value of cos2A is 0.68

Given : The value of sin A is 0.4

To find : The value of cos 2A

Solution :

We can simply solve this mathematical problem by using the following mathematical process. (our goal is to calculate the value of cos 2A)

Here, we will be using general trigonometric formula.

First of all, we have to calculate the value of sin²A.

So,

sin A = 0.4

sin² A = (0.4)² = 0.16

Now,

= cos 2A

= 1 - 2 sin²A

= 1 - (2×0.16)

= 1 - 0.32

= 0.68

(This will be considered as the final result.)

Used formula :

• cos 2x = 1 - 2sin²x

Hence, the value of cos2A is 0.68