more or less right but not an answer to the question.The attached circuit implements the mathematical relationship between the sine and cosine trigonometric functions. Mathematically, if you integrate a sine wave, you get an inverted cosine wave. Basically, it's the same waveform but shifted 90° in phase. Then, if you integrate that cosine wave, you get another 90° phase shift, producing a negative sine wave. Of course, each op amp integrator introduces an inversion as well, so the output of the first integrator is actually a non-inverted cosine wave. This is reversed again by the second integrator, so its output is still a negative sine wave. All we have to do is invert that negative sine wave to get our original sine wave back again. The attached circuit accomplishes this.
the AC side is far so easy , integrating a square wave twice gives a sine wave and integrating triangle waves output sine wave but what if i apply Dc voltage at the input side of Opamp ? how it will generate sin output ?Do you really need a circut that ouptus the sine of an arbitrary input signal? If you have a particular type of input signal in your application, it will be easier to come up wth a circuit to take the sine of it.