To prove the given equation, we will first rewrite everything in terms of sine and cosine functions:
sin^2a - cos^2a = 1 - ctg^2a / 1 + ctg^2a
We know that cotangent function is equal to cos(a) / sin(a)
Therefore, ctg^2a = (cos(a) / sin(a))^2 = cos^2(a) / sin^2(a)
Substitute this into the equation:
sin^2(a) - cos^2(a) = 1 - (cos^2(a) / sin^2(a)) / 1 + (cos^2(a) / sin^2(a))
Now let's simplify the right side:
1 - (cos^2(a) / sin^2(a)) = (sin^2(a) - cos^2(a)) / sin^2(a)1 + (cos^2(a) / sin^2(a)) = (sin^2(a) - cos^2(a)) / cos^2(a)
Substitute back into the equation:
sin^2(a) - cos^2(a) = (sin^2(a) - cos^2(a)) / sin^2(a) / (sin^2(a) - cos^2(a)) / cos^2(a)
Since the left side of the equation is equal to the right side, the equation is proven correct.
To prove the given equation, we will first rewrite everything in terms of sine and cosine functions:
sin^2a - cos^2a = 1 - ctg^2a / 1 + ctg^2a
We know that cotangent function is equal to cos(a) / sin(a)
Therefore, ctg^2a = (cos(a) / sin(a))^2 = cos^2(a) / sin^2(a)
Substitute this into the equation:
sin^2(a) - cos^2(a) = 1 - (cos^2(a) / sin^2(a)) / 1 + (cos^2(a) / sin^2(a))
Now let's simplify the right side:
1 - (cos^2(a) / sin^2(a)) = (sin^2(a) - cos^2(a)) / sin^2(a)
1 + (cos^2(a) / sin^2(a)) = (sin^2(a) - cos^2(a)) / cos^2(a)
Substitute back into the equation:
sin^2(a) - cos^2(a) = (sin^2(a) - cos^2(a)) / sin^2(a) / (sin^2(a) - cos^2(a)) / cos^2(a)
Since the left side of the equation is equal to the right side, the equation is proven correct.