Trigonometry

Prove the following statements. tanA/1-cotA+cotA/1-tanA=(secA.cosecA+1)

Note by Alok Patel
7 years, 6 months ago

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Comments

In the right hand side of the equation, do you mean sec A csc A + 1\text{sec A csc A + 1} or sec A (csc A +1)\text{sec A (csc A +1)}?

敬全 钟 - 7 years, 6 months ago

Here's how I did it:

tanA1cotA\frac{tanA}{1-cotA} + cotA1tanA\frac{cotA}{1-tanA}

= sinAcosA1cosAsinA\frac{\frac{sinA}{cosA}}{1-\frac{cosA}{sinA}} + cosAsinA1sinAcosA\frac{\frac{cosA}{sinA}}{1-\frac{sinA}{cosA}}

= sin2AcosA(sinAcosA)\frac{sin^{2}A}{cosA(sinA-cosA)} + cos2AsinA(cosAsinA)\frac{cos^{2}A}{sinA(cosA-sinA)}

= sin3Acos3AsinAcosA(sinAcosA)\frac{sin^{3}A-cos^{3}A}{sinAcosA(sinA-cosA)}

= (sinAcosA)(sin2A+sinAcosA+cos2A)sinAcosA(sinAcosA)\frac{(sinA-cosA)(sin^{2}A+sinAcosA+cos^{2}A)}{sinAcosA(sinA-cosA)}

= sin2A+sinAcosA+cos2AsinAcosA\frac{sin^{2}A+sinAcosA+cos^{2}A}{sinAcosA}

= 1+sinAcosAsinAcosA\frac{1+sinAcosA}{sinAcosA}

= 1+1sinAcosA1+\frac{1}{sinAcosA}

= 1 + secAcosecA

Hope you understood.

Ajay Maity - 7 years, 6 months ago

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Thank you to help me in problem solving

Alok patel - 7 years, 6 months ago

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You are welcome!

Ajay Maity - 7 years, 6 months ago
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