Question

if sin a=0.4 find value of cos 3a​

Answer 1

Answer:

by using cos(3A)=4cos3A - 3 cos A

4(0.4)2 - 3 cos alfa

0.256-1.2

cos (3A)= _0.944

Answer 2

If sin a = 0.4 then sin 3a = 0.944

Given :

sin a = 0.4

To find :

The value of sin 3a

Formula :

sin 3a = 3 sin a - 4sin³ a

Solution :

Step 1 of 2 :

Write down the given value

Here it is given that sin a = 0.4

Step 2 of 2 :

Find the value of sin 3a

sin 3a

= 3 sin a - 4sin³ a

= 3 × 0.4 - 4 × (0.4)³

= 1.2 - 4 × 0.064

= 1.2 - 0.256

= 0.944

Correction in the question :

There is a change in question .

Correct question is : if sin A=0.4 then find sin 3A

Correct question link :

https://brainly.in/question/13044162

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