Brittany A.
asked 11/15/12I need help trying to sole tan^2 x =1 where x is more than or equal to 0 but x is less than or equal to pi
this is what it looks like tan^2 x=1 where 0 ≤ x ≤ π
4 Answers By Expert Tutors

Tamara J. answered 11/15/12
Math Tutoring - Algebra and Calculus (all levels)
tan2(x) = 1 , 0 ≤ x ≤ Π
tan2(x) = 1 ==> (tan(x))2 = 1
√(tan(x))2 = √1 ==> tan(x) = ± 1
Note the following: tan(x) = sin(x)/cos(x)
So, tan(x) = ± 1 ==> sin(x)/cos(x) = ± 1
Multiply both sides of the equation by cos(x):
(cos(x))·(sin(x)/cos(x)) = (cos(x))·(± 1)
sin(x) = ± cos(x)
Looking at the top half of a unit circle (where x is between 0 and Π)...
...find the coordinates where sin(x) = cos(x) and sin(x) = -cos(x)
You will see that the coordinates that match are (√2/2, √2/2), which is located at x = ∏/4, and (-√2/2, √2/2), which is located at x = 3Π/4.
Thus, x = Π/4 and x = 3Π/4

Elena B.
Excellent explanation!
11/18/12

Robert J. answered 11/15/12
Certified High School AP Calculus and Physics Teacher
Solve for tan x first, tan x = ±1
Therefore, x = pi/4, 3pi/4 on [0, pi]

Osman A. answered 12/19/21
Professor of Engineering Mathematics – Trigonometry and Geometry
I need help trying to sole tan2 x = 1 where x is more than or equal to 0 but x is less than or equal to pi. this is what it looks like tan^2 x=1 where 0 ≤ x ≤ π
Detailed Solution:
tan2 x = 1 0 ≤ x ≤ π
tan x = ±1
tan x = 1 (Quadrant 1 only in 0 ≤ x ≤ π)
x = tan-1 1 = π/4
tan x = –1 (Quadrant 2 only in 0 ≤ x ≤ π)
x = tan-1 –1 = π – π/4 = 3π/4
x = (π/4, 3π/4)
tan^2(x) = 1
take the square root of both sides
tanx = + or -1 at this point you could recognize it's a 1-1- sqr2 right triangle that's 45 degrees Or you could plug in 1 into a calculator with an inverse trig function, and it would read 45 degrees or pi/4, plug in -1 and the inverse tangent will probably say -45 degrees. Add 180 to -45 to get 135 degrees. You want quadrant I and II, not IV where -45 degrees is.
There're an infinite number of solutions, but only two if the solutions are resticted to 0<angle<pi
answer is 45 and 135 degrees or pi/4 and 3pi/4 radians
another method is
tan^2(x) = 1
tan^2(x) -1=0
factor
(tanx +1)(tanx-1) = 0
set each factor = 0
tanx =-1 or +1
reference angle is 45 degrees,
x =45 or 180-45 = 135
convert to radians
x =pi/4 or 3pi/4
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Brittany A.
thanks
11/15/12