Math, asked by srinethi15, 1 year ago

the value of sin square 18+sin square72

Answers

Answered by pmtibrahim18
2

sin2 72 + sin2 18

we know sin 90 - theta = cos theta

and here theta is 18

so sin2 (90 - 18 ) = cos 2 72

so

sin2 72 + cos2 72 = 1

cuz of formula

sin2 theta + cos2 theta =1

Answered by Agastya0606
1

The value of sin²18+sin²72 is 1.

Given,

A trigonometric expression sin²18+sin²72.

To Find,

The value of this trigonometric expression.

Solution,

The given trigonometric expression is

sin²18+sin²72

Using the formula

sin(90-θ) = cosθ

Now,

sin(90-72) = cos 72

Similarly, sin²(90-72) = cos²(72)

sin²18 = cos²72

Substituting the value in the given expression

cos²72+sin²72

Using the identity, sin²θ+cos²θ = 1

So,

cos²72+sin²72 = 1

Hence, the value of sin²18+sin²72 is 1.

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