Question

please help me.....,...

Answer 1

The correct answer is (d) 1.

By using complementary angles you will get your answer.

Answer 2

As,

sin ( x+y) = sinx. cosy+ cosx. sin y.

sin75= sin45.cos30+ cos45.sin30. since,

sin30= 1/2,cos30=√3/2,sin45=cos45=1/√2

then sin75= √3+1/2√2.

cos 15,

cos( a-b) = cosa.cosb- sina. sinb.

putting x and y are 45,30.

cos15= cos(45-30)

cos15= cos45.cos30- sin45.sin30.

cos15= √3+1/2√2.

if we solve sin75 and cos15 that value is equal to 2+ √3/4..

hope it helps u ..

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