5 stars for who solve this math idetity.?
sin(A/2)^2 = sinAtanA/2secA+2
2007-12-19 00:49:08 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
This is NOT an identity:
Two counterexamples:
1). A = 0: The left side is 0, but the right side is 2.
2). A = π: The left side is 1, but the right side is undefined.
2007-12-19 02:16:19 · answer #1 · answered by steiner1745 7 · 0⤊ 0⤋
You mean
sin²(A/2) = sinAtanA/2secA+2
Taking RHS
sinAtanA/2secA+2
sinAsinA/cosA / 2/cosA + 2 (multiply up nd down by cosA)
sin²A / 2cosA+2
sin²A / 2(2cos²A/2 -2 ) +2
(2sinA/2cosA/2)² / 4cos²A/2
4sin²A/2cos²A/2 / 4cos²A/2
sin²A/2
(sinA/2)²â¡(sinA/2)² (proved )
2007-12-19 09:09:09 · answer #2 · answered by Murtaza 6 · 1⤊ 1⤋
the identity is wrong!!!
put A=0
you end up getting
zero = zero + 2
ie 0=2 !!!!
and mastermind's answer is wrong at the 3rd line coz the cosA vanishes from the denominator when u simplify
2007-12-19 09:09:46 · answer #3 · answered by supercool_ash 2 · 0⤊ 3⤋
Pretty clever I say, Most people will look at that and say"WTH!". It seems very solvable but I dont have my calculator handy at the moment. So I say, you win this one but beware the next time.
2007-12-19 08:59:25 · answer #4 · answered by The Punisher 3 · 0⤊ 4⤋