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sec^2xtanx=2tanx

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asked Jul 18, 2014 in TRIGONOMETRY by anonymous

1 Answer

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The trigonometric equation is sec2 (x) tan x = 2tan(x).

tan x[ sec2 (x) - 2] = 0

⇒tan x = 0 and sec2 (x) - 2 = 0.

tan x = 0.

tan x = tan 0.

The genaral solution of tan(θ) = tan(α) is θ = nπ + α, where n is an integer.

⇒ x = nπ + 0

x = .n = 0,1,2........

sec2 (x) - 2 = 0

sec2 (x) = 2

Using reciprocal identity : sec2 x = 1/cos2 x .

(1/cos2 x) = 2

1 = 2cos2 x

cos2 x = 1/2

cos x = ±1/2.

cos x = 1/and  cos x = - 1/2.

cos (x) = 1/2.

cos (x) = cos(π/4)

The genaral solution of cos(θ) = cos(α) is θ = 2nπ ± α, where n is an integer.

x = 2nπ ± π/4 : n = 0,1,2........

os (x) = -1/2.

cos (x) = cos(3π/4)

The genaral solution of cos(θ) = cos(α) is θ = 2nπ ± α, where n is an integer.

x = 2nπ ± 3π/4 : n = 0,1,2........

answered Jul 18, 2014 by bradely Mentor

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