Theory |
by Example Series Function Inverse / Manipulation |
(a) (b)
Solutions:
(a) divide by 3, take ln, divide by 2:
(b) )
Question 2. Solve for x
(a) 1.04x = 3 (b) e0.044x = 6
(c) log(1-x) - log (1+x) = 2 (optional - extra points)
Solutions:
(a) take ln: x ln (1.04) = ln 3, x = ln 3 / ln 1.04 = x = 28.01
(b) take ln: 0.044 x = ln 6, x = ln 6 / 0.044 = x = 40.7218
(c)
Solve for x:
(check: )
Question 3 - Find the inverse function of the following i.e. x = f(y):
(a) y = e45x - 1 (b) y =
Solutions:
(a) ln y = ln (e45x - 1)=45x - 1, 45x = ln(y) + 1,
(b) y = , square both sides:
Question 4. Solve for x :
(a) (b) |x - 3| = 7
Solutions:
(a) 10log N = N, so
So x = 2
(b) |x - 3| = 7, So x-3 = +7 and x-3 = -7 (since abs make both positive 7)
x- 3 = +7 , x = 10
x - 3 = -7, x = -4
So x = -4 or 10
Question 5. Find 2 values of x when the following 2 equations are equal:
y = 10 (2)x and y = 10 + 15 x
Both equal 10 when x = 0 (y-intercept)
And when graphs intersect at x = 2 (plotting both functions in calculator)