11Sin 36 = sin(90-54)
2Sin18Cos18 = Cos 54
2Sin18Cos18 = 4cos318 - 3cos18
2sin18 = 4 cos218 -3
2sin18 = 1-4sin218
Therefore quadratic equation
Sin 18 = √5 - 1/4
Cos 36 = 1 - 2 Sin218
Thus
Cos 36 = 1+√5/4
In a triangle ABC, angle A = 36°, AB = AC = 1 and BC = x . If x = (p + √q)/2 then the ordered pair (p,q) is
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8 Answers
11Cos A =(1 +√5)/4
So
Cos A = 1 + x2 - 1/2*1*x
Cos A = x/2
(1 +√5)/4 = x/2
x = (1 + √5)/2
p + √q = 1 + √5
p = 1
q =5
11
6hey cud u pls make me understand the meaning of this question....
62basically you have to find x..
once you have done that, you have to find p and q which satisfy the condition there.. by comparing of coefficients :)
6p n q r the coefficients of sin n cos??actually wat does p n q signify??i hav seen these variables in many ordered pair q.s.
62no they are not...
it is basically if you get cos A = 3+4√5 then p=3, q=4