Prove the following :4(sin430° + cos4 60°) – 3(cos2 45° – sin290°) = 2

We know that,Sin (90o) = 1Now solving, L.H.S.= 4[{(sin 30o)2}2 + {(cos 60o)2}2] – 3[(cos 45o)2 - (sin 90o)2]Putting the values=2 = R.H.S.Hence Proved

Q5 of 268 Page 4

Prove the following :
4(sin⁴30° + cos⁴ 60°) – 3(cos² 45° – sin²90°) = 2

We know that,

Sin (90^o) = 1

Now solving, L.H.S.

= 4[{(sin 30^o)²}² + {(cos 60^o)²}²] – 3[(cos 45^o)² - (sin 90^o)²]

Putting the values

=2 = R.H.S.

Hence Proved

Prove the following :

When α =60°

Prove the following :

cos(A – B) = cos A. cos B + sinA . sin B if A=B=60^o

Prove the following :

sin90° = 2sin45°.cos45°

Prove the following :

cos60° = 2cos²30° – 1 = 1 – 2 sin²30°