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If x+y=90^(@), which of the following mu...

If `x+y=90^(@)`, which of the following must be true?

A

cosx=cosy

B

sin x=-sin y

C

tan x=cot y

D

sin x+cos y=1

Text Solution

Verified by Experts

The correct Answer is:
C
Confunctions of complementary angles are equal. Since x and y are complementary, tan and cot are cofunctions. An alternative solution is to choose any values of x and y such that their sum is `90^(@)`. (for example, `x=40^(@) and y=50^(@)`). Test the answer choices with your calculator in degree mode to see that only choice C is true.
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