Question

cos square 67 minus sin square 63

Answer 1

Hi ,

There is an error in the question.

cos² 67 - sin² 23

= cos² 67 - sin² ( 90 - 67 )

= cos² 67 - cos² 67

[ Since sin( 90 - x ) = cos x ]

= 0

I hope this helps you.

: )

Answer 2

To find:

Cos^2 67 -  Sin^2 23

Solution:

By formula,

Cos^2A - Sin^2B = Cos ( A + B ) * Cos ( A - B )

Here,

A = 67

B = 23  

Substituting,

We get,

Cos (67 + 23 ) * Cos( 67 - 23 )

Cos ( 90 ) * cos ( 45  )

Substituting values,

0 * 1/√2 .

Hence, Cos^2 67 -  Sin^2 23 = 0

Read more on Brainly.in - https://brainly.in/question/3110172