Posted by **Marlanea** on Monday, October 1, 2012 at 9:45pm.

Find the value of c where the line l tangent to the graph of y=2.5*5^x at (0,2.5) intersects the x-axis

- Calculus -
**Reiny**, Monday, October 1, 2012 at 9:56pm
dy/dx = 2.5(5^x)ln5

when x=0 from (0, 2.5)

dy/dx = 2.5ln5

so tangent is y= 2.5ln5 x + c

at (0 , 2.5)

2.5 = 0 + c

so the equation is y = 2.5ln5 x + 2.5

at the x-axis, y =0

0 = 2.5ln5 x + 2.5

2.5ln5 x = -2.5

ln5 x = -1

x = -1/ln5 or appr -.62

## Answer this Question

## Related Questions

- Calculus - Find the value of c where the line l tangent to the graph of y=2.5*5^...
- Calc - A line tangent to y=(x^2)+1 at x=a, a>0, intersects the x-axis at ...
- Calc. - Find the area of the region bounded by the parabola y=x^2, the tangent ...
- calculus - Let f(x)=(x^2)+x+14. What is the value of f(x) for which the tangent ...
- Calculus - Given the function defined as f(x)=x^3-(3/2)x^2-6x+10 a) Explain why ...
- Calculus - Given the function defined as f(x)=x^3-(3/2)x^2-6x+10 a) Explain why ...
- Calculus - The graph of the equation x2 − xy + y2 = 9 is an ellipse. Find ...
- calculus - 5. Let for and f(x)=12X^2 for x>=0 and f(x)>=0 a. The line ...
- math - With regards to question J: The variables x and y are connected by the ...
- calculus - let f be the function f(x) = x^3 + 3x^2 - x + 2 a. the tangent to the...