# Question #e8251

##### 1 Answer

Jan 18, 2018

a.

b.

c.

#### Explanation:

cool, its very simple;)

the identity is,

comparing your questions to this identity,

a.

so here

b.

so here

c.

now this one needs a lil simplification,

and now, the identity can be applied again to

that's like,

so here

hope this gives you an idea about the identity:)

-Sahar