Question

1) if sin x = 2/3, find the value of sin 3 x

2) if cos x = -2/5 , find the value of cos 3 x
3) prove that •• cos 2x + 2 sin²x = 1
​

Answer 1

Answer:

hope it's helpful mrk me as brainleast plz

Answer 2

Answer:

ap on nhi aate ho Kya

apse bat nhi ho pati

Step-by-step explanation:

We know that : <br> Mass number = Atomic number + No. of neutrons <br> So, 23 = Atomic number + 12 <br> And, Atomic number = 23 - 12 <br> = 11 <br> The element having atomic number 11 is sodium and its symbol is Na. If, however, we indicate the atomic number and mass number also, then the symbol becomes

, where 11 is the atomic number and 23 is the mass number.