The solution of equation 13 – 4 cos2x = 12 sin x is?
13-4(1-2sin²x)= 12sinx
13-4+8sin²x=12sinx
8sin²x-12sinx+9=0
sinx=-b+-√b²-4ac/2a
= +12+-√-144/2×8
= 12+-12i/16
= 3+-3i/4
The solution of equation 13 – 4 cos2x = 12 sin x is?
**Solution:**
To solve the equation 13 - 4cos^2(x) = 12sin(x), we will follow the steps mentioned below:
**Step 1: Simplify the equation**
Let's simplify the equation by using the identity cos^2(x) = 1 - sin^2(x):
13 - 4(1 - sin^2(x)) = 12sin(x)
Simplifying further:
13 - 4 + 4sin^2(x) = 12sin(x)
9 + 4sin^2(x) - 12sin(x) = 0
**Step 2: Substitute sin(x) with a new variable**
Let's substitute sin(x) with a new variable, say t. So, the equation becomes:
4t^2 - 12t + 9 = 0
**Step 3: Solve the quadratic equation**
We can solve this quadratic equation by factoring or using the quadratic formula. Let's use the quadratic formula:
t = (-b ± sqrt(b^2 - 4ac))/2a
Here, a = 4, b = -12, and c = 9. Substituting these values into the quadratic formula:
t = (-(-12) ± sqrt((-12)^2 - 4(4)(9)))/(2(4))
Simplifying further:
t = (12 ± sqrt(144 - 144))/8
t = (12 ± sqrt(0))/8
**Step 4: Find the values of t**
Since the discriminant (144 - 144) is zero, the equation has only one real root:
t = 12/8
t = 3/2
**Step 5: Substitute back the value of t to find sin(x)**
Now, we substitute the value of t back into the equation sin(x) = t:
sin(x) = 3/2
However, sin(x) cannot be greater than 1, so there is no solution for sin(x) = 3/2.
Therefore, the given equation 13 - 4cos^2(x) = 12sin(x) has no solution.
So, the solution to the equation is the empty set, {} or Ø.
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