Question

Using the realation cos (A+B) =cosB -sinAsinB, find the value of cos 75 degree.​

Answer 1

Answer:

bhai 8th standard me hu ye sums abhi bhi nhi sikhi mene.

agar ant ko elephant uthane ko bologe toh wo kar payegi nhi na waise hi me nhi janti ye solution. sorry

Answer 2

Answer:

COS 75 = (root 3 - 1)/2

Step-by-step explanation:

let,

A = 45 degrees

B = 30 degrees

then ,

cos (A+B)= cos Acos B - sin Asin B

applying the values of A and B

cos( 45 + 30 ) = cos 45.cos 30 - sin 45.sin 30

cos 75 = (1/root 2)(root 3/2) - (1/root 2)(1/2)

cos 75 = (root 6/2) - (root 2/2)

cos 75 = (root 3/root 2) - (1/root 2)

cos 75 = root 3 - 1

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