Math, asked by shivam246, 1 year ago

1 + cos theta equal to

Answers

Answered by rksharma2580
0
2cos²theta/2 ............
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Answered by abhi178
2
1 + cos∅ = 2cos²(∅/2)
actually ,
cos2∅ = cos²∅ - sin²∅
= cos²∅ - (1 - cos²∅)
= 2cos²∅ - 1

cos2∅ = 2cos²∅ -1
cos2∅ + 1 = 2cos²∅ we use this concept here,


that's why , 1 + cos∅ = 2cos²(∅/2)
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