Now we will discuss about the Pythagorean
triplets when the angle(α) is twice (i.e.2α),
or when it is 3α or is α/2.
Now, First of
For
alltwice the angle(2α):
Angle Triplet
α (p,b,h)
2α (2pb,b²-p²,h²)
g. (i) If Sinα = 3/5
Then, Tan2α = ?
lution: We have,
Sinα = 3/5
, p=3 and h=5
the Pythagorean triplet is (3,4,5)
w, the triplet for 2α:
(2×3×4,4²-3²,5²) = (24,7,25)
, p’=24, b’=7 and h’=25 (sides of new triangle)
en,
Tan2α = p’/b’ = 24/7
If Cosα = 40/41
Then, Cos2α = ?
ution: We have,
Cosα = 40/41
b=40 and h=41
the Pythagorean triplet is (9,40,41)
w, the triplet for 2α:
(2×9×40,40²-9²,41²) = (720,1519,1681)
p’=720, b’=1519 and h’=1681 (sides of new trian
en,
Cos2α = b’/h’ = 1519/1681
Now,
For thrice the angle(3α):
Angle Triplet
α (p,b,h)
3α (3ph²-4p³,4b³-3bh²,h³)
) If Tanα = 7/24
Then, Cos3α = ?
on: We have,
Tanα = 7/24
p=7 and b=24
Pythagorean triplet is (7,24,25)
he triplet for 3α:
3×7×(25)²-4×7³,4×(24)³-3×24×(25)²,(25)³) = (11753,1029
=11753, b’=10296 and h’=15625 (sides of new tria
Cos3α = b’/h’ = 10296/15625
f Sinα = 3/5
Then, Tan3α = ?
ion: We have,
Sinα = 3/5
p=3 and h=5
he Pythagorean triplet is (3,4,5)
the triplet for 3α:
(3×3×5²-4×3³,4×4³-3×4×5²,5³) = (117,-44,125)
’=117, b’=-44 and h’=125 (sides of new triangle)
,
Tan3α = p’/b’ = -117/44
Now,
For half the angle(α/2):
Angle Triplet
α (p,b,h)
α/2 (p,b+h,√(b+h)²+p²)
g. (i) If Sinα = 12/13
Then, Tanα/2 = ?
lution: We have,
Sinα = 12/13
, p=12 and h=13
the Pythagorean triplet is (12,5,13)
w, the triplet for α/2:
(12,5+13,√(5+13)²+12²) = (12,18,6√13)
, p’=12, b’=18 and h’=6√13 (sides of new triangle)
en,
Tanα/2 = p’/b’ = 12/18 = 2/3
) If Cosα = 4/5
Then, Cosα/2 = ?
lution: We have,
Cosα = 4/5
, b=4 and h=5
the Pythagorean triplet is (3,4,5)
ow, the triplet for α/2:
(3,4+5,√(4+5)²+3²) = (3,9,3√10)
, p’=3, b’=9 and h’=3√10 (sides of new triangle)
en,
Cosα/2 = b’/h’ = 9/3√10 = 3/√10