Math, asked by seenvasreddy, 1 year ago

express the ratios cos A, tan A and sec A in terms of sin A.
in the given sollution it is said that cos A is positive when A is acute.. plzz explain this point.

Answers

Answered by kaushikravikant

cosa= (1- sin^2A)^1/2
secA=1/cosa= 1/(1-sin^2A)^1/2
tana=(sec^2A - 1 )^1/2
tanA = { (1/1- sin^2A) - 1 }^1/2 = sin^2A / (1- sin^2A)

as angle is acute means angle lies in 1st quardent and all trigonometry function are positive in 1st quardent hence cos is also positive when there is acute angle.

seenvasreddy: from where this acute angle is taken and why it is mentioned here answer this question plzz

kaushikravikant: if it is acute angle then all trigonometry ratio will be positive, if angle lies in 2nd quadrant then only sine and cosecent ratjo will positive, if angle lie in 3 rd quardant then tan and cot will positivd ,if angle lie in 4th quardant then cos and sec will politics

seenvasreddy: plzz prove it that cos A is positive when A is acute

kaushikravikant: i don't know dear

Answered by ritudave281

Answer:

proof:in ∆abc it is right angle triangle

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express the ratios cos A, tan A and sec A in terms of sin A. in the given sollution it is said that cos A is positive when A is acute.. plzz explain this point.

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express the ratios cos A, tan A and sec A in terms of sin A.
in the given sollution it is said that cos A is positive when A is acute.. plzz explain this point.