Question

If cot A=7/8 , then evaluate 1. (1+sinA) (1-sinA) 2. tanA×cotA​

Answer 1

Answer:

Step-by-step explanation:

1)

Given,

        cotA = 7 / 8

Here, we said to evaluate :

⇒ ( 1 + sinA )( 1 - sinA )

⇒ { 1^2 -( sinA )^2 }

⇒ ( 1 - sin^2 A )

From the properties of trigonometry :

1 - sin^2 A = cos^2 A

1 - cos^2 A = sin^2 A

Using these :

⇒ ( cos^2 A ) / ( sin^2 A )

⇒ ( cosA / sinA )^2

⇒ ( cotA )^2                     { We know, cotA = sinA / cosA }

⇒ ( 7 / 8 )^2

⇒ 49 / 64.

2) tanA =1/cot A

tanA=8/7

tanA x CotA=8/7 x 7/8=1

tanA x CotA=1

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Answer 2

Answer:

i can give answer no. 2 only

Step-by-step explanation:

tanA× cotA

BC/AB ×AB/BC

8/7 × 7/8

=0

BECAUSE 7 and 8 will be cut because it is recipocal of other