<h2>
Answer:</h2>
cos 28°cos 62°– sin 28°sin 62° = 0
<h2>
Step-by-step explanation:</h2>
From one of the trigonometric identities stated as follows;
<em>cos(A+B) = cosAcosB - sinAsinB -----------------(i)</em>
We can apply such identity to solve the given expression.
<em>Given:</em>
cos 28°cos 62°– sin 28°sin 62°
<em>Comparing the given expression with the right hand side of equation (i), we see that;</em>
A = 28°
B = 62°
<em>∴ Substitute these values into equation (i) to have;</em>
<em>⇒ cos(28°+62°) = cos28°cos62° - sin28°sin62°</em>
<em />
<em>Solve the left hand side.</em>
<em>⇒ cos(90°) = cos28°cos62° - sin28°sin62°</em>
⇒ 0 = <em>cos28°cos62° - sin28°sin62° (since cos 90° = 0)</em>
<em />
<em>Therefore, </em>
<em>cos28°cos62° - sin28°sin62° = 0</em>
<em />
<em />
Answer: D. x=72
Step-by-step explanation:
With the equation x/8-6=3 we can start solving by first moving the "-6"
x/8-6(<u>+6)</u>=3(+6)
x/8=9 <-- Rewrite equation after adding "6" to both sides
x/8(*8)=9(*8) <--- Multiply both sides by 8
x=72 <-- After multiplying, solution is found
The points of (9,1) after a 270 degree counterclockwise rotation would be (1,-9)
Hope this helps!
