Verify the pythagorean identity.
Answers
Convert to sines and cosines:-
1 + cot^2 x
= 1 + cos^2 x / sin^2x
= sin^2 x + cos^2 x
sin^2 x
but sin^2 x + cos^2 x = 1
so this = 1 / sin^2x which is the same as csc^2 x
1 + cot² t = csc² t
[tex]1+cot ^{2} t = \frac{1}{sin ^{2} t} \\ 1+ \frac{cos^{2}t }{sin^{2}t } = \frac{1}{sin ^{2} t}[/tex] / * sin² t
sin² t + cos² t = 1
1 = 1
We have confirmed the identity.
The identity is verified. See the explanation.
Step-by-step explanation:
You must keep on mind the following identities:
[tex]csc\theta=\frac{cos\theta}{sin\theta}\\\\csc\theta=\frac{1}{sin\theta}\\\\sin^2\theta+cos^2\theta=1[/tex]
Therefore, by substitution, you can rewrite the identity as shown below:
[tex]1+cot^2\theta=csc^2\theta\\\\1+\frac{cos^2\theta}{sin^2\theta}=csc^2\theta[/tex]
Simpliying, you obtain:
[tex]\frac{sin^2\theta+cos^2\theta}{sin^2\theta}=csc^2\theta\\\\\frac{1}{sin^2\theta}=csc^2\theta\\\\csc^2\theta=csc^2\theta[/tex]
The identity is verified.
To prove this Pythagorean Identity, we have to know that:
cot = 1 / tan
and we also know that:
tan = sin / cos
Therefore,
cot = 1 / tan = cos / sin
So we can write the given equation in the form of:
1 + (cos^2 θ / sin^2 θ) = csc^2 θ
Expanding the left hand side of the equation:
(sin^2 θ / sin^2 θ) + (cos^2 θ / sin^2 θ) = csc^2 θ
(sin^2 θ + cos^2 θ) / sin^2 θ = csc^2 θ
We know that given a unit circle, sin^2 θ + cos^2 θ = 1. So:
1 / sin^2 θ = csc^2 θ
The equation above is already true basing on the trigonometric identities. Therefore:
csc^2 θ = csc^2 θ
This is pretty simple.
If you have a sheet that tells you your identities then you should see that
[tex]1+cot^{2}=csc^{2}[/tex]
Just change
[tex]1+cot^{2}[/tex] to [tex]csc^{2}[/tex]
and get
[tex]csc^{2}=csc^{2}[/tex]