In 9 hours
john earns $67.5
becky earns $74.25
becky earns $6.75 more than john
Sec^2 x - 1 = tan^2x
Proof:
Sec^2x = 1+ tan^2x
1/cos^2x = 1 + sin^2x/cos^2x
<span>1/cos^2x - sin^2x/cos^2x = 1
</span>Using common denominator:
(1-sin^2x)/cos^2x = 1
sin^2x + cos^2 x = 1
cos^2 x = 1 - sin^2x
Substituting :
cos^2x/<span>cos^2x = 1
</span>1 = 1
Left hand side = right hand side
f(x) = x² - 8x + 5 Plug in -1 for all of the x-values
f(-1) = (-1)² - 8 (-1) + 5 Square -1
f(-1) = 1 - 8 (-1) + 5 Multiply -8 and -1
f(-1) = 1 + 8 + 5 Add
f(-1) = 14
