A、<img class=\""kfformula\"" src=\""data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAJAAAAA1CAYAAACul2LlAAAGwElEQVR4Xu2cZ4gsRRCAv2fOOWJCMSAYUVQQA+oPEyZMmEXMYM45YMKcMSdUFAMoiigGBFEUMWNAVFRMiDlnPqyBecvNztxOuL29bjgetzfdXV39TVV1de2bRmpJAzU0MK1G39Q1aYAEUIKglgYSQLXUlzongBIDtTSQAKqlvtQ5AZQYqKWBBFAt9aXOCaDEQC0NJIBqqS91TgAlBmppIAFUS32pcwKoOQY2AdYCLmxuyOEfKQFUf49WAbYE9gDuBs6rP+TkGSEB1NxenQr8lQBqTqFTbaQE0BTZ8fWAbYGngFWBd4BHG1h7AqgBJQ77EIsDlwGnAR8AZwL\/xr9\/1BQ+AVRTgZOh+zLAXcBrwC3AKxG3NCF7AqgJLQ75GB4adF9HABsBTwL7Ap+E3EsBOwEzl6zjY+B+IG+1EkBDvvl1xROeuYBfw+p4\/L4x8jbCULclgOpqcMj7m+S7DTgGeAyYN+C5Dni5AdkTQA0ocZiHmA84CHgX+BFYF3geeDoC6UFlN65aETggBrgeeBv4dNABJ1O\/lEicTLs1hLImgIZwUyaTSAmgybRbQyhrFwAtNITrnkoifd3mYrsAaP02F5DGLtXAc6VP1HigC4DGEm9ZYFHghRqyt9F1SWA54NmCwdcAfo9TVhvzDzpmmdyDjlvabyIAWgHYPXIwP5dK2O0D6mPXyDD3Jhe1pGsDVzd4\/dHU6vrJ3dQcY47TNUCzAicADwKvh0RuzG7AGcAvkav5Ariz1ZX\/P\/hYVYTzAKcAVwFeWdjmj88uBj6LzxYA9otrkM0jp3RTB3C5Z76AfwL35HQ0ltytq7BrgNYBtg9YdAU2AfJiU8vk5aaZ4VvDVbSlgLIqwh0AE4SXhgD+7j3ZFZF09EU4GrgXeB9YLK5FzHALXhttxiiZ3Q7YBTipByDn7JW7DTmmG7NrgA4PhT+Sk0KA9OH5t6nOwt1Ma36cw7e0Xyu6fhCeY2OTfotyD+V7NQZbKS5ltUh\/x2dHApsCewLfDrCAqnLPHmCbQe\/VWV7uHwaQYdxdugRo7oh7rgTeahEgN3ef2HQ3fxCA8rIKwzkB0+cxmIA+EPM8Hp\/pVoTIGEqrNN5WVe5+ABXpeLyyVH6+S4AWjnph3\/psIxRUC7RhQGV5xIdxX5UtYqbYKG\/SBW9j4Abgo4JVVt0IuxdZIN3FWcDDwHfAIcCJQBb0zwC4Wf5uHbR6FB7BOjAs0JzAoYB5GH\/WDBdYZJ2qyt0PoLzcnZxwuwRIBRmcHtZj4r0l3yAXO5wdt+P3BSC6hR2Bo4AFI14yNikqQ626Ef0Ayv72XlyKGuQb8xRZtCWAm2MNQmczwLYCUutl6ayx3cE5N9jLf1W5+wGUl7upkKCvNRoGgHoF3CZOZd5u68f93eD1ckCovOW2DLWoVd2IpgDSQhovaam0jFokmxZpb+CSKB\/5qsQvVJV7ygJkgHd6vMmZGc+KvHQF\/4SCdWnCksUSugKtjzGGSj43V8OsK7HC0HKKrHm8Xj2SgVmA698Mqt\/s2cR+NTxaS0+FphQMjE0\/9Fog5fdE5KnMtEMGj9Posk1NbAUo0\/HAtTF\/HbnLAMrkzh9UStgd\/M9dWiBzKboeYwsL2m3LA3dEbPRQfGY85DN7Rc5Fhf0UcYauxLhCmLIxBnUF\/SyQc14UBWjfACcHxPn4Rd3pWmeLLxQKj6kI80Se\/mYJuYXLF8D6I8tn24yB8nK\/ODgW1Xt2CZAK1XrohrIAT+tihaBvpiZeeaxX9l+tkPHSZpFctG7ZQNSA9rgGNqIfQF4Anx8gfx8wXdBzujJuWzqO0sLj5gmKZbJaGysedWO64S3ioKBFyvJfg4LfzwLl5c6SoNVpGODJLgFSPC2HliifbDNBtz\/wBuAdmdloM7rWLq8GbA28BMwRiTTjjKwIfqwlV4klyqoIDey1Lm64J0MtkO4scwtaGi2nViXfrgkXrRvWjfrtj0UiCSlYWrOiVkXulcNdm0\/zRGoqwTmycfNyF4E6ACbFXboGyNOK1sPvZflmt9GqbES\/edVJtkFPxIOCvHNYpLrfH6sD0HjlbkO\/043ZNUBObnDsvP5HBG00T0VZ3NTvtFY0t2+5MurCtII28yu6U4vvi27q666lDbnrylTafyIAUlG6rGeGsCzC5KCyeaL6skd7xmvGX7eP8bdSRbf8QD+5W516IgByQR5jPb0Y7wxTM9C3Fbkp4fen7Iqk6zWVyd2aPBMFUGsLSgN3q4EEULf6HrnZEkAjt6XdLigB1K2+R262BNDIbWm3C0oAdavvkZstATRyW9rtghJA3ep75Gb7D3oOhUUYKXc6AAAAAElFTkSuQmCC\"" data-latex=\""\\frac {s-1} {(5s+1)(2s+1)}\"">
B、<img class=\""kfformula\"" src=\""data:image\/png;base64,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\"" data-latex=\""\\frac {1-Ts} {1+{T}_{1}s}\"">(T>0)
C、<img class=\""kfformula\"" src=\""data:image\/png;base64,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\"" data-latex=\""\\frac {s+1} {(2s+1)(3s+1)}\"">
D、<img class=\""kfformula\"" src=\""data:image\/png;base64,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\"" data-latex=\""\\frac {s+2} {s(s+3)(s-2)}\"">