Question

if 3 cot a equal to 4 check the whether 1-tan square a/1+tan square a equal to cos square a - sin square a or not

Answer 1

I hope it helps your

Answer 2

Solution:

Given 3cotA = 4 [ this information is not required to

prove the given data ]

Now ,

LHS = (1-tan²A)/(1+tan²A)

= [1-(sin²A/cos²A)]/[1+(sin²A/cos²A)]

/* tanA = sinA/cosA */

= [(cos²A-sin²A)/cos²A]/[(cos²A+sin²A)/cos²A]

After cancellation,we get

= (cos²A - sin²A)/(cos²A+sin²A)

= cos²A - sin²A

/* By Trigonometric identity:

cos²A + sin²A = 1 */

= RHS

Therefore:

(1-tanA)/(1+tanA) = cos²A-sin²A

is true.

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