Deepak Kumar Shringi
Last Activity: 6 Years ago
We are given:
sin⁴A - cos⁴A = 1
Step 1: Use the identity for difference of squares
The given expression can be simplified using the identity:
a² - b² = (a - b)(a + b)
Here, let:
a = sin²A
b = cos²A
Now,
sin⁴A - cos⁴A = (sin²A - cos²A)(sin²A + cos²A)
Since sin²A + cos²A = 1 (from the Pythagorean identity),
sin⁴A - cos⁴A = (sin²A - cos²A)(1)
=> sin⁴A - cos⁴A = sin²A - cos²A
Step 2: Solve for sin²A - cos²A
Given that sin⁴A - cos⁴A = 1,
sin²A - cos²A = 1
From the identity,
sin²A - cos²A = cos(2A)
So,
cos(2A) = 1
Step 3: Find the value of A
cos(2A) = 1 occurs when:
2A = 0°, 360°, 720°, ...
=> A = 0°, 180°, 360°, ...
Step 4: Find A/2
From the possible values of A,
If A = 0°, A/2 = 0°
If A = 180°, A/2 = 90°
If A = 360°, A/2 = 180°
Thus, the possible values of A/2 are 0°, 90°, 180°, ...