Respuesta :

irspow
let the two sides of a right triangle be equal to one, which means that the hypotenuse is √2

Since cosa=adjacent side / hypotenuse

cos45=1/√2

We can rationalize the denominator by multiplying numerator and denominator by √2

√(2)/2

or if you prefer:  √(1/2)

The exact value of  cos 45° = 1/√2

What is exact value?

"It is a value that is known with complete certainty."

What are exact values of trigonometric functions?

"These are values of certain angles that can be expressed exactly using expressions containing real numbers."

For given example,

We need to find the exact value of  cos 45°.

The exact value of  cos 45° is 1/√2.

If we convert 1/√2 in decimal form it would be,

⇒ 1/√2 = 0.707106…

If we consider this decimal till thousandth place, then it would be

⇒ 1/√2 = 0.707...

But this value is an exact value, its an approximate value.

Therefore, the exact value of  cos 45° = 1/√2

Learn more about exact value here:

https://brainly.com/question/4960142

#SPJ2

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