Question

what is the value of (cos square 67-sin square 23)?

Answer 1

cos²67° – sin²23°
⇒ cos²(90°–23°) – sin²23°
⇒ sin²23° – sin²23°
⇒ 0

OR

cos²67° – sin²23°
⇒ cos²67° – sin²(90°–67°)
⇒ cos²67° – cos²67°
⇒ 0

Hope This Helps :)

Answer 2

Hi ,

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We know that ,

sin ( 90 - x ) = cos x

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Now ,

cos² 67° - sin² 23°

= cos² 67° - sin² ( 90 - 67° )

= cos² 67 - cos² 67

= 0

I hope this helps you .

: )