Please help me with this

asked May 17, 2020 2.8k views

3 votes

by Mpdc

6.8k points

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1 vote

Answer:

(√(51) )/(10)

Explanation:

Using the Pythagorean identity

sin²x + cos²x = 1 ⇒ cosx = ±
√(1-sin^2x) , hence

cosΘ =
√(1-(7/10)^2)

=
$\sqrt{1-(49)/(100) }$

=
$\sqrt{(51)/(100) }$

=
(√(51) )/(√(100) ) =
(√(51) )/(10)

MrHohn answered May 23, 2020

6.9k points

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