You have the following:
2cot2θ - 3cscθ = 0
Start by adding "3cscθ" to both sides:
2cot2θ = 3cscθ
Next, put the equation in terms of sine and cosine. This will make it easier to work with.
2cos2θ/sin2θ = 3/sinθ
Multiply both sides by sinθ to simplify:
2cos2θ/sinθ = 3
Multiply both sides by sinθ again, so the sinθ is on the other side:
2cos2θ = 3sinθ
Using the Pythagorean trigonometric identity (cos2θ + sin2θ = 1), we can put the equation entirely in terms of sine:
2(1 - sin2θ) = 3sinθ
2 - 2sin2θ = 3sinθ
Add 2sin2θ and subtract 2 from both sides, so the terms are all on one side:
0 = 2sin2θ + 3sinθ - 2
Notice how the equation looks similar to a quadratic equation. We can factor the equation just like a quadratic equation, so we get:
0 = (2sinθ - 1)(sinθ + 2)
If either piece is equal to zero, the entire equation is equal to zero. All we have to do is solve each part seperately for zero.
2sinθ - 1 = 0
2sinθ = 1
sinθ = 1/2
θ = pi/3 or 2pi/3
--
sinθ + 2 = 0
sinθ = -2
The second piece has no solution. The only two answers within the interval [0, 2pi] are pi/3 and 2pi/3.
Cot(90) = 0 so 1/cot(90), if defined, would be 1/0. Such a fraction is not defined and that is what is wrong with the sentence.
Solve this problem -x squared -40x- 80 =0
a2+30a+56=0 , solve for a Using the quadratic formula, you will find that: a=-2 , a=-28
By factoring. q2 + 16q = 0 q (q + 16) = 0 Now, either q = 0, or q + 16 = 0. Solve those two equations to get the solution.
9x2-9x = 0 x2-x = 0 x(x-1) = 0 x = 1 or x = 0
From math class, some trigonometric identities: cot x = 1/tan x csc x = 1/sin x sec x = 1/cos x There are no built-in cot or csc formulas, so use the above. Remember that these give errors when tan x, sin x, or cos x are equal to 0.
Sin= 0 Cos= -1 Tan= 0 Csc= undef. Sec= -1 Cot= undef.
sin(90°) = 1 cos(90°) = 0 tan(90°) = ∞ sec(90°) = ∞ csc(90°) = 1 cot(90°) = 0
2sinx+1 equals 0
For y - 2y - 3y equals 0, y equals 0.
There is no value cot 0, because cot 0 is equivalent to 1 / tan 0, which is equivalent to 1 / 0, which is undefined. That said, the limit of cot x as x approaches 0 is infinity.
Cot(90) = 0 so 1/cot(90), if defined, would be 1/0. Such a fraction is not defined and that is what is wrong with the sentence.
many solutions
"x equals 0" is an equality, not an inequality. The question is, therefore, not consistent.
Suppose x3-4x = 0. To solve, factor: x3-4x = x(x2-4) = x(x+2)(x-2) = 0 Now, a product equals 0 if and only one or more of the factors equals 0, so set each factor to 0 and solve. The roots are 0,-2 and +2.
x: x2 - 81 = 0
Solve this problem -x squared -40x- 80 =0