Saturday

August 2, 2014

August 2, 2014

Posted by **Hannah** on Tuesday, September 7, 2010 at 11:28pm.

f(x)= sin x 0<x<3pi/4

cos x 3pi/4<x<2pi

at x = 3pi/4

- Calculus -
**bobpursley**, Wednesday, September 8, 2010 at 12:29amThe real question is the f' continous at the point.

below the point: f'=cos x, at the point, f'=-.707

f' above the point; f'=-sinx, at the point, f'=-.707

so, the derivative curve is continous, and the curve has a tangent.

- Calculus -
**Hannah**, Wednesday, September 8, 2010 at 7:42amThank you. Can you tell me how to actually work the problem, too? Thanks again!

- Calculus -
**MathMate**, Wednesday, September 8, 2010 at 9:22amAnother condition for tangency at x0=(3/4)π is that f(x0) must exist.

In this particular case,

Lim f(x0-)=(√2)/2 and

Lim f(x0+)=-(√2)/2

so f(x) is discontinuous at x=x0.

In fact, f(x) is undefined at x=x0, or x0 is not in the domain of f(x).

The tangent does not exist at x0, even though the derivative (slope) is continuous throughout the function.

**Related Questions**

trig - Solve cos x-1 = sin^2 x Find all solutions on the interval [0,2pi) a. x=...

Pre-Calculus-check answers - State the period and phase shift of the function y...

Calculus - Find the slope of the tangent line to the curve 2sin(x) + 6cos(y) - ...

Math - Test for symmetry with repsect to Q=pi/2, the polar axis, and the pole. ...

Math - Test for symmetry with repsect to Q=pi/2, the polar axis, and the pole. r...

maths - Please can you help me with this question? Choose the option which is a ...

trig - Solve the equation for cos theta-tan theta=0 for greater than or egual to...

Calculus - 1) The period of a trig. function y=sin kx is 2pi/k. Then period of y...

CALC HW - FIND THE X VALUES OF ALL POINTS, -2PI LESS THAN OR EQUAL TO X LESS ...

trig - if tan x= 4/3 and pip < x < 3pi/2, and cot y= -5/12 with 3pi/2 <...