She would be 67...always going to be 3 years younger
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.
You want to use PEMDAS for this.
<em>P</em>= arenthesis ( )
<em>E</em>= xponents a²
<em>M</em>= ultiply ×
<em>D</em>= ivide ÷
<em>A</em>= dd +
<em>S</em>= ubtract -
What you want to do is go in order and ask yourself as you go.
Are there any <u><em>Parenthesis</em></u>? <em>No
</em>Are there any <u><em>Exponents</em></u><em />? <em>No</em>
Is there any <em /><u><em>Multiplication</em></u><em />? <em>Yes
</em><em />Is there any <em><u>Division</u></em>? <em>No
</em><em />Is there any <em><u>Addition</u></em>? <em>No
</em><em />Is there any <em><u>Subtraction</u></em><u />? <em>Yes</em><em>
</em><em />Thats when you stop and you multiply what you have in the PEMDAS. Top to bottom. 3x5 which gives you 15. Now you equation is 45-15. Thats when you subtract and you get your answer which is 30.
Ok well since it said “how much more we subtract 11-7=4
