Show using the law of cosine that if (Y)= 90degrees then c^2=a^2+b^2?

0 ⤊

Y=gamma

2007-04-14 13:56:24 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

c^2 = a^2+b^2-2ab(cos90)

cos 90 = 0

c^2 = a^2 + b^2 - 0

2007-04-14 13:59:08 · answer #1 · answered by richardwptljc 6 · 0⤊ 0⤋

a² = b² + c² - 2ab*cos(y) is the law of cosines. So at y = 90°, cos(Y) = cos(90°) = 0 and
a² = b² + c²

HTH ☺

Doug

2007-04-14 14:02:36 · answer #2 · answered by doug_donaghue 7 · 0⤊ 0⤋

at 90 degrees, cos(90) = 0
so the term that has the cos in it, is zero, and can be dropped, leaving the c^2 = a^2 + b^2

2007-04-14 13:59:28 · answer #3 · answered by bz2hcy 3 · 0⤊ 0⤋

I think that just killed all the brain cells i've had left.
There now officially alllllll gone!
GOODBYE BRAIN CELLS!!!!
I'll miss you!!!!!

2007-04-14 13:59:02 · answer #4 · answered by BRIT™ 3 · 0⤊ 0⤋