Can anyone help me with trig identities?

Mathematics

1 answer:

nevsk [136]3 years ago

6 0

Answer:

cosA = √(21/25)

Step-by-step explanation:

We know

sin²(A) + cos²(A) = 1

Next, we know that sin(A) = 2/5. Plugging that into our equation, we get

(2/5)² + cos²A = 1

4/25 + cos²A = 1

subtract 4/25 from both sides to isolate cos²A

cos²A = 1 - 4/25 = 25/25-4/25 = 21/25

square root both sides to get

cosA = √(21/25)

We do not include -√(21/25) in our possible answer for cosA because this is in quadrant 1, so cosA must be positive.

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wel

Answer:

$y=-\frac{2}{3} x+4$

Step-by-step explanation:

move the variable to the right(-2x) and change the sign(2x now) -3y=-12+2x then change the signs (-3y is 3y , -12 is 12 and then 2x becomes -2x again) then divide both sides of the equation by 3 so 12÷3=4 and -2x÷3= $-\frac{2}{3} x$ then you're going to use the commutative property to reorder the terms . so your answer is $y=-\frac{2}{3} x+4$