Q. 12 B4.2( 5 Votes )

Let us write whether the following statements are true of false:

(i) The value of cos54° and sin36° are equal.

(ii) The simplified value of (sin 12° - cos78°) is 1.

Answer :

(i) The statement is true

cos54° = cos(90 - 36)°

= sin36°

[cos(90 - θ) = sinθ]

the value of cos54° and sin36° has same values

(ii) The given statement is False

sin12° - cos78°

sin12° - cos(90 - 12)°

sin12° - sin12°

= 0

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